Taking a sleeping lock to _only_ increment a variable is quite the
overkill, and pretty much all users do this. Furthermore, some drivers
(ie: infiniband and scif) that need pinned semantics can go to quite
some trouble to actually delay via workqueue (un)accounting for pinned
pages when not possible to acquire it.
By making the counter atomic we no longer need to hold the mmap_sem and
can simply some code around it for pinned_vm users. The counter is 64-bit
such that we need not worry about overflows such as rdma user input
controlled from userspace.
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
The perf_proc_update_handler() handles /proc/sys/kernel/perf_event_max_sample_rate
syctl variable. When the PMU IRQ handler timing monitoring is disabled, i.e,
when /proc/sys/kernel/perf_cpu_time_max_percent is equal to 0 or 100,
then no modification to sysctl_perf_event_sample_rate is allowed to prevent
possible hang from wrong values.
The problem is that the test to prevent modification is made after the
sysctl variable is modified in perf_proc_update_handler().
You get an error:
$ echo 10001 >/proc/sys/kernel/perf_event_max_sample_rate
echo: write error: invalid argument
But the value is still modified causing all sorts of inconsistencies:
$ cat /proc/sys/kernel/perf_event_max_sample_rate
10001
This patch fixes the problem by moving the parsing of the value after
the test.
Committer testing:
# echo 100 > /proc/sys/kernel/perf_cpu_time_max_percent
# echo 10001 > /proc/sys/kernel/perf_event_max_sample_rate
-bash: echo: write error: Invalid argument
# cat /proc/sys/kernel/perf_event_max_sample_rate
10001
#
Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1547169436-6266-1-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To avoid having to change many call sites everytime we want to add a
parameter use a structure to group all parameters for the mmu_notifier
invalidate_range_start/end cakks. No functional changes with this patch.
[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
From: Jérôme Glisse <jglisse@redhat.com>
Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3
fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n
Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf updates from Ingo Molnar:
"The main changes in this cycle on the kernel side:
- rework kprobes blacklist handling (Masami Hiramatsu)
- misc cleanups
on the tooling side these areas were the main focus:
- 'perf trace' enhancements (Arnaldo Carvalho de Melo)
- 'perf bench' enhancements (Davidlohr Bueso)
- 'perf record' enhancements (Alexey Budankov)
- 'perf annotate' enhancements (Jin Yao)
- 'perf top' enhancements (Jiri Olsa)
- Intel hw tracing enhancements (Adrian Hunter)
- ARM hw tracing enhancements (Leo Yan, Mathieu Poirier)
- ... plus lots of other enhancements, cleanups and fixes"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (171 commits)
tools uapi asm: Update asm-generic/unistd.h copy
perf symbols: Relax checks on perf-PID.map ownership
perf trace: Wire up the fadvise 'advice' table generator
perf beauty: Add generator for fadvise64's 'advice' arg constants
tools headers uapi: Grab a copy of fadvise.h
perf beauty mmap: Print mmap's 'offset' arg in hexadecimal
perf beauty mmap: Print PROT_READ before PROT_EXEC to match strace output
perf trace beauty: Beautify arch_prctl()'s arguments
perf trace: When showing string prefixes show prefix + ??? for unknown entries
perf trace: Move strarrays to beauty.h for further reuse
perf beauty: Wire up the x86_arch prctl code table generator
perf beauty: Add a string table generator for x86's 'arch_prctl' codes
tools include arch: Grab a copy of x86's prctl.h
perf trace: Show NULL when syscall pointer args are 0
perf trace: Enclose the errno strings with ()
perf augmented_raw_syscalls: Copy 'access' arg as well
perf trace: Add alignment spaces after the closing parens
perf trace beauty: Print O_RDONLY when (flags & O_ACCMODE) == 0
perf trace: Allow asking for not suppressing common string prefixes
perf trace: Add a prefix member to the strarray class
...
Pull RCU updates from Ingo Molnar:
"The biggest RCU changes in this cycle were:
- Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.
- Replace calls of RCU-bh and RCU-sched update-side functions to
their vanilla RCU counterparts. This series is a step towards
complete removal of the RCU-bh and RCU-sched update-side functions.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- Documentation updates, including a number of flavor-consolidation
updates from Joel Fernandes.
- Miscellaneous fixes.
- Automate generation of the initrd filesystem used for rcutorture
testing.
- Convert spin_is_locked() assertions to instead use lockdep.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- SRCU updates, especially including a fix from Dennis Krein for a
bag-on-head-class bug.
- RCU torture-test updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits)
rcutorture: Don't do busted forward-progress testing
rcutorture: Use 100ms buckets for forward-progress callback histograms
rcutorture: Recover from OOM during forward-progress tests
rcutorture: Print forward-progress test age upon failure
rcutorture: Print time since GP end upon forward-progress failure
rcutorture: Print histogram of CB invocation at OOM time
rcutorture: Print GP age upon forward-progress failure
rcu: Print per-CPU callback counts for forward-progress failures
rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings
rcutorture: Dump grace-period diagnostics upon forward-progress OOM
rcutorture: Prepare for asynchronous access to rcu_fwd_startat
torture: Remove unnecessary "ret" variables
rcutorture: Affinity forward-progress test to avoid housekeeping CPUs
rcutorture: Break up too-long rcu_torture_fwd_prog() function
rcutorture: Remove cbflood facility
torture: Bring any extra CPUs online during kernel startup
rcutorture: Add call_rcu() flooding forward-progress tests
rcutorture/formal: Replace synchronize_sched() with synchronize_rcu()
tools/kernel.h: Replace synchronize_sched() with synchronize_rcu()
net/decnet: Replace rcu_barrier_bh() with rcu_barrier()
...
due to a missing mutex protection.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCXAlffRQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qq0KAP0eIy6/kwoBocygRLgB6N4naX/zFcw4
m2NiSlYe3NpC6AD/Z1g3wg8bKlm7ar2OzaqE4wQdeKjrvPlUtymUKiwFxA8=
=8Huu
-----END PGP SIGNATURE-----
Merge tag 'trace-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"This is a single commit that fixes a bug in uprobes SDT code due to a
missing mutex protection"
* tag 'trace-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
Uprobes: Fix kernel oops with delayed_uprobe_remove()
There could be a race between task exit and probe unregister:
exit_mm()
mmput()
__mmput() uprobe_unregister()
uprobe_clear_state() put_uprobe()
delayed_uprobe_remove() delayed_uprobe_remove()
put_uprobe() is calling delayed_uprobe_remove() without taking
delayed_uprobe_lock and thus the race sometimes results in a
kernel crash. Fix this by taking delayed_uprobe_lock before
calling delayed_uprobe_remove() from put_uprobe().
Detailed crash log can be found at:
Link: http://lkml.kernel.org/r/000000000000140c370577db5ece@google.com
Link: http://lkml.kernel.org/r/20181205033423.26242-1-ravi.bangoria@linux.ibm.com
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reported-by: syzbot+cb1fb754b771caca0a88@syzkaller.appspotmail.com
Fixes: 1cc33161a8 ("uprobes: Support SDT markers having reference count (semaphore)")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull RCU changes from Paul E. McKenney:
- Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.
- Replace calls of RCU-bh and RCU-sched update-side functions
to their vanilla RCU counterparts. This series is a step
towards complete removal of the RCU-bh and RCU-sched update-side
functions.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- Documentation updates, including a number of flavor-consolidation
updates from Joel Fernandes.
- Miscellaneous fixes.
- Automate generation of the initrd filesystem used for
rcutorture testing.
- Convert spin_is_locked() assertions to instead use lockdep.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- SRCU updates, especially including a fix from Dennis Krein
for a bag-on-head-class bug.
- RCU torture-test updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix two typos in kernel/events/*.
No change in functionality intended.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can be
replaced by synchronize_rcu(). This commit therefore makes this change.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Commit:
142b18ddc8 ("uprobes: Fix handle_swbp() vs unregister() + register() race")
added the UPROBE_COPY_INSN flag, and corresponding smp_wmb() and smp_rmb()
memory barriers, to ensure that handle_swbp() uses fully-initialized
uprobes only.
However, the smp_rmb() is mis-placed: this barrier should be placed
after handle_swbp() has tested for the flag, thus guaranteeing that
(program-order) subsequent loads from the uprobe can see the initial
stores performed by prepare_uprobe().
Move the smp_rmb() accordingly. Also amend the comments associated
to the two memory barriers to indicate their actual locations.
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: stable@kernel.org
Fixes: 142b18ddc8 ("uprobes: Fix handle_swbp() vs unregister() + register() race")
Link: http://lkml.kernel.org/r/20181122161031.15179-1-andrea.parri@amarulasolutions.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf updates and fixes from Ingo Molnar:
"These are almost all tooling updates: 'perf top', 'perf trace' and
'perf script' fixes and updates, an UAPI header sync with the merge
window versions, license marker updates, much improved Sparc support
from David Miller, and a number of fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits)
perf intel-pt/bts: Calculate cpumode for synthesized samples
perf intel-pt: Insert callchain context into synthesized callchains
perf tools: Don't clone maps from parent when synthesizing forks
perf top: Start display thread earlier
tools headers uapi: Update linux/if_link.h header copy
tools headers uapi: Update linux/netlink.h header copy
tools headers: Sync the various kvm.h header copies
tools include uapi: Update linux/mmap.h copy
perf trace beauty: Use the mmap flags table generated from headers
perf beauty: Wire up the mmap flags table generator to the Makefile
perf beauty: Add a generator for MAP_ mmap's flag constants
tools include uapi: Update asound.h copy
tools arch uapi: Update asm-generic/unistd.h and arm64 unistd.h copies
tools include uapi: Update linux/fs.h copy
perf callchain: Honour the ordering of PERF_CONTEXT_{USER,KERNEL,etc}
perf cs-etm: Correct CPU mode for samples
perf unwind: Take pgoff into account when reporting elf to libdwfl
perf top: Do not use overwrite mode by default
perf top: Allow disabling the overwrite mode
perf trace: Beautify mount's first pathname arg
...
Back in January I posted patches to create function based events. These were
the events that you suggested I make to allow developers to easily create
events in code where no trace event exists. After posting those changes for
review, it was suggested that we implement this instead with kprobes.
The problem with kprobes is that the interface is too complex and needs to
be simplified. Masami Hiramatsu posted patches in March and I've been
playing with them a bit. There's been a bit of clean up in the kprobe code
that was inspired by the function based event patches, and a couple of
enhancements to the kprobe event interface.
- If the arch supports it (we added support for x86), you can place a
kprobe event at the start of a function and use $arg1, $arg2, etc
to reference the arguments of a function. (Before you needed to know
what register or where on the stack the argument was).
- The second is a way to see array of events. For example, if you reference
a mac address, you can add:
echo 'p:mac ip_rcv perm_addr=+574($arg2):x8[6]' > kprobe_events
And this will produce:
mac: (ip_rcv+0x0/0x140) perm_addr={0x52,0x54,0x0,0xc0,0x76,0xec}
Other changes include
- Exporting trace_dump_stack to modules
- Have the stack tracer trace the entire stack (stop trying to remove
tracing itself, as we keep removing too much).
- Added support for SDT in uprobes
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCW9hdjxQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qmtbAP9GS/o2WSvsYLSIw4+mF94eCL06lUxp
rRrktkEofm/PagEAl2JNmvHrAJN+LIrajqXTbwlZ7Ckk1rZhCW41Am7qnQs=
=sTUM
-----END PGP SIGNATURE-----
Merge tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The biggest change here is the updates to kprobes
Back in January I posted patches to create function based events.
These were the events that you suggested I make to allow developers to
easily create events in code where no trace event exists. After
posting those changes for review, it was suggested that we implement
this instead with kprobes.
The problem with kprobes is that the interface is too complex and
needs to be simplified. Masami Hiramatsu posted patches in March and
I've been playing with them a bit. There's been a bit of clean up in
the kprobe code that was inspired by the function based event patches,
and a couple of enhancements to the kprobe event interface.
- If the arch supports it (we added support for x86), you can place a
kprobe event at the start of a function and use $arg1, $arg2, etc
to reference the arguments of a function. (Before you needed to
know what register or where on the stack the argument was).
- The second is a way to see array of events. For example, if you
reference a mac address, you can add:
echo 'p:mac ip_rcv perm_addr=+574($arg2):x8[6]' > kprobe_events
And this will produce:
mac: (ip_rcv+0x0/0x140) perm_addr={0x52,0x54,0x0,0xc0,0x76,0xec}
Other changes include
- Exporting trace_dump_stack to modules
- Have the stack tracer trace the entire stack (stop trying to remove
tracing itself, as we keep removing too much).
- Added support for SDT in uprobes"
[ SDT - "Statically Defined Tracing" are userspace markers for tracing.
Let's not use random TLA's in explanations unless they are fairly
well-established as generic (at least for kernel people) - Linus ]
* tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (24 commits)
tracing: Have stack tracer trace full stack
tracing: Export trace_dump_stack to modules
tracing: probeevent: Fix uninitialized used of offset in parse args
tracing/kprobes: Allow kprobe-events to record module symbol
tracing/kprobes: Check the probe on unloaded module correctly
tracing/uprobes: Fix to return -EFAULT if copy_from_user failed
tracing: probeevent: Add $argN for accessing function args
x86: ptrace: Add function argument access API
tracing: probeevent: Add array type support
tracing: probeevent: Add symbol type
tracing: probeevent: Unify fetch_insn processing common part
tracing: probeevent: Append traceprobe_ for exported function
tracing: probeevent: Return consumed bytes of dynamic area
tracing: probeevent: Unify fetch type tables
tracing: probeevent: Introduce new argument fetching code
tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions
tracing: probeevent: Cleanup argument field definition
tracing: probeevent: Cleanup print argument functions
trace_uprobe: support reference counter in fd-based uprobe
perf probe: Support SDT markers having reference counter (semaphore)
...
Replace a bunch of spaces with tab, cleans up indentation
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/20181029233211.21475-1-colin.king@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull siginfo updates from Eric Biederman:
"I have been slowly sorting out siginfo and this is the culmination of
that work.
The primary result is in several ways the signal infrastructure has
been made less error prone. The code has been updated so that manually
specifying SEND_SIG_FORCED is never necessary. The conversion to the
new siginfo sending functions is now complete, which makes it
difficult to send a signal without filling in the proper siginfo
fields.
At the tail end of the patchset comes the optimization of decreasing
the size of struct siginfo in the kernel from 128 bytes to about 48
bytes on 64bit. The fundamental observation that enables this is by
definition none of the known ways to use struct siginfo uses the extra
bytes.
This comes at the cost of a small user space observable difference.
For the rare case of siginfo being injected into the kernel only what
can be copied into kernel_siginfo is delivered to the destination, the
rest of the bytes are set to 0. For cases where the signal and the
si_code are known this is safe, because we know those bytes are not
used. For cases where the signal and si_code combination is unknown
the bits that won't fit into struct kernel_siginfo are tested to
verify they are zero, and the send fails if they are not.
I made an extensive search through userspace code and I could not find
anything that would break because of the above change. If it turns out
I did break something it will take just the revert of a single change
to restore kernel_siginfo to the same size as userspace siginfo.
Testing did reveal dependencies on preferring the signo passed to
sigqueueinfo over si->signo, so bit the bullet and added the
complexity necessary to handle that case.
Testing also revealed bad things can happen if a negative signal
number is passed into the system calls. Something no sane application
will do but something a malicious program or a fuzzer might do. So I
have fixed the code that performs the bounds checks to ensure negative
signal numbers are handled"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
signal: Guard against negative signal numbers in copy_siginfo_from_user32
signal: Guard against negative signal numbers in copy_siginfo_from_user
signal: In sigqueueinfo prefer sig not si_signo
signal: Use a smaller struct siginfo in the kernel
signal: Distinguish between kernel_siginfo and siginfo
signal: Introduce copy_siginfo_from_user and use it's return value
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
signal: Fail sigqueueinfo if si_signo != sig
signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
signal/unicore32: Use force_sig_fault where appropriate
signal/unicore32: Generate siginfo in ucs32_notify_die
signal/unicore32: Use send_sig_fault where appropriate
signal/arc: Use force_sig_fault where appropriate
signal/arc: Push siginfo generation into unhandled_exception
signal/ia64: Use force_sig_fault where appropriate
signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
signal/ia64: Use the generic force_sigsegv in setup_frame
signal/arm/kvm: Use send_sig_mceerr
signal/arm: Use send_sig_fault where appropriate
signal/arm: Use force_sig_fault where appropriate
...
This patch enables uprobes with reference counter in fd-based uprobe.
Highest 32 bits of perf_event_attr.config is used to stored offset
of the reference count (semaphore).
Format information in /sys/bus/event_source/devices/uprobe/format/ is
updated to reflect this new feature.
Link: http://lkml.kernel.org/r/20181002053636.1896903-1-songliubraving@fb.com
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Some of the scheduling tracepoints allow the perf_tp_event
code to write to ring buffer under different cpu than the
code is running on.
This results in corrupted ring buffer data demonstrated in
following perf commands:
# perf record -e 'sched:sched_switch,sched:sched_wakeup' perf bench sched messaging
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run
Total time: 0.383 [sec]
[ perf record: Woken up 8 times to write data ]
0x42b890 [0]: failed to process type: -1765585640
[ perf record: Captured and wrote 4.825 MB perf.data (29669 samples) ]
# perf report --stdio
0x42b890 [0]: failed to process type: -1765585640
The reason for the corruption are some of the scheduling tracepoints,
that have __perf_task dfined and thus allow to store data to another
cpu ring buffer:
sched_waking
sched_wakeup
sched_wakeup_new
sched_stat_wait
sched_stat_sleep
sched_stat_iowait
sched_stat_blocked
The perf_tp_event function first store samples for current cpu
related events defined for tracepoint:
hlist_for_each_entry_rcu(event, head, hlist_entry)
perf_swevent_event(event, count, &data, regs);
And then iterates events of the 'task' and store the sample
for any task's event that passes tracepoint checks:
ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->attr.type != PERF_TYPE_TRACEPOINT)
continue;
if (event->attr.config != entry->type)
continue;
perf_swevent_event(event, count, &data, regs);
}
Above code can race with same code running on another cpu,
ending up with 2 cpus trying to store under the same ring
buffer, which is specifically not allowed.
This patch prevents the problem, by allowing only events with the same
current cpu to receive the event.
NOTE: this requires the use of (per-task-)per-cpu buffers for this
feature to work; perf-record does this.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
[peterz: small edits to Changelog]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: e6dab5ffab ("perf/trace: Add ability to set a target task for events")
Link: http://lkml.kernel.org/r/20180923161343.GB15054@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we unregister a PMU, we fail to serialize the @pmu_idr properly.
Fix that by doing the entire thing under pmu_lock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 2e80a82a49 ("perf: Dynamic pmu types")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We assume to have only one reference counter for one uprobe.
Don't allow user to register multiple uprobes having same
inode+offset but different reference counter.
Link: http://lkml.kernel.org/r/20180820044250.11659-3-ravi.bangoria@linux.ibm.com
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Userspace Statically Defined Tracepoints[1] are dtrace style markers
inside userspace applications. Applications like PostgreSQL, MySQL,
Pthread, Perl, Python, Java, Ruby, Node.js, libvirt, QEMU, glib etc
have these markers embedded in them. These markers are added by developer
at important places in the code. Each marker source expands to a single
nop instruction in the compiled code but there may be additional
overhead for computing the marker arguments which expands to couple of
instructions. In case the overhead is more, execution of it can be
omitted by runtime if() condition when no one is tracing on the marker:
if (reference_counter > 0) {
Execute marker instructions;
}
Default value of reference counter is 0. Tracer has to increment the
reference counter before tracing on a marker and decrement it when
done with the tracing.
Implement the reference counter logic in core uprobe. User will be
able to use it from trace_uprobe as well as from kernel module. New
trace_uprobe definition with reference counter will now be:
<path>:<offset>[(ref_ctr_offset)]
where ref_ctr_offset is an optional field. For kernel module, new
variant of uprobe_register() has been introduced:
uprobe_register_refctr(inode, offset, ref_ctr_offset, consumer)
No new variant for uprobe_unregister() because it's assumed to have
only one reference counter for one uprobe.
[1] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
Note: 'reference counter' is called as 'semaphore' in original Dtrace
(or Systemtap, bcc and even in ELF) documentation and code. But the
term 'semaphore' is misleading in this context. This is just a counter
used to hold number of tracers tracing on a marker. This is not really
used for any synchronization. So we are calling it a 'reference counter'
in kernel / perf code.
Link: http://lkml.kernel.org/r/20180820044250.11659-2-ravi.bangoria@linux.ibm.com
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
[Only trace_uprobe.c]
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
It has been pointed out to me many times that it is useful to be able to
switch off AUX records to save the bandwidth for records that actually
matter, for example, in AUX overwrite mode.
The usefulness of PERF_RECORD_AUX is in some of its flags, like the
TRUNCATED flag that tells the decoder where exactly gaps in the trace
are. The OVERWRITE flag, on the other hand will be set on every single
record in overwrite mode. However, a PERF_RECORD_AUX[flags=OVERWRITE] is
generated on every target task's sched_out, which over time adds up to a
lot of useless information.
If any folks out there have userspace that depends on a constant stream
of OVERWRITE records for a good reason, they'll have to let us know.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Link: http://lkml.kernel.org/r/20180404145323.28651-1-alexander.shishkin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For userspace to tell the difference between a random signal and an
exception, the exception must include siginfo information.
Using SEND_SIG_FORCED for SIGILL is thus wrong, and it will result
in userspace seeing si_code == SI_USER (like a random signal) instead
of si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.
Therefore replace force_sig_info(SIGILL, SEND_SIG_FORCE, current)
with force_sig(SIG_ILL, current) which gets this right and is
shorter and easier to type.
Fixes: 014940bad8 ("uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails")
Fixes: 0b5256c7f1 ("uprobes: Send SIGILL if handle_trampoline() fails")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Perf can record user stack data in response to a synchronous request, such
as a tracepoint firing. If this happens under set_fs(KERNEL_DS), then we
end up reading user stack data using __copy_from_user_inatomic() under
set_fs(KERNEL_DS). I think this conflicts with the intention of using
set_fs(KERNEL_DS). And it is explicitly forbidden by hardware on ARM64
when both CONFIG_ARM64_UAO and CONFIG_ARM64_PAN are used.
So fix this by forcing USER_DS when recording user stack data.
Signed-off-by: Yabin Cui <yabinc@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 88b0193d94 ("perf/callchain: Force USER_DS when invoking perf_callchain_user()")
Link: http://lkml.kernel.org/r/20180823225935.27035-1-yabinc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Kernel:
- Modify breakpoint fixes (Jiri Olsa)
perf annotate:
- Fix parsing aarch64 branch instructions after objdump update (Kim Phillips)
- Fix parsing indirect calls in 'perf annotate' (Martin Liška)
perf probe:
- Ignore SyS symbols irrespective of endianness on PowerPC (Sandipan Das)
perf trace:
- Fix include path for asm-generic/unistd.h on arm64 (Kim Phillips)
Core libraries:
- Fix potential null pointer dereference in perf_evsel__new_idx() (Hisao Tanabe)
- Use fixed size string for comms instead of scanf("%m"), that is
not present in the bionic libc and leads to a crash (Chris Phlipot)
- Fix bad memory access in trace info on 32-bit systems, we were reading
8 bytes from a 4-byte long variable when saving the command line in the
perf.data file. (Chris Phlipot)
Build system:
- Streamline bpf examples and headers installation, clarifying
some install messages. (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQR2GiIUctdOfX2qHhGyPKLppCJ+JwUCW41FnAAKCRCyPKLppCJ+
J8MCAP4/RC5GwNrO5KYJ+G1iYb7QiNq9X/wsM7jCBlqWnTH+zgD9GYPIT3WQWKBN
Rv94N4PNsYP4cpP7hTzWG0ar7p70owo=
=+ODq
-----END PGP SIGNATURE-----
Merge tag 'perf-urgent-for-mingo-4.19-20180903' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
Kernel:
- Modify breakpoint fixes (Jiri Olsa)
perf annotate:
- Fix parsing aarch64 branch instructions after objdump update (Kim Phillips)
- Fix parsing indirect calls in 'perf annotate' (Martin Liška)
perf probe:
- Ignore SyS symbols irrespective of endianness on PowerPC (Sandipan Das)
perf trace:
- Fix include path for asm-generic/unistd.h on arm64 (Kim Phillips)
Core libraries:
- Fix potential null pointer dereference in perf_evsel__new_idx() (Hisao Tanabe)
- Use fixed size string for comms instead of scanf("%m"), that is
not present in the bionic libc and leads to a crash (Chris Phlipot)
- Fix bad memory access in trace info on 32-bit systems, we were reading
8 bytes from a 4-byte long variable when saving the command line in the
perf.data file. (Chris Phlipot)
Build system:
- Streamline bpf examples and headers installation, clarifying
some install messages. (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We can safely enable the breakpoint back for both the fail and success
paths by checking only the bp->attr.disabled, which either holds the new
'requested' disabled state or the original breakpoint state.
Committer testing:
At the end of the series, the 'perf test' entry introduced as the first
patch now runs to completion without finding the fixed issues:
# perf test "bp modify"
62: x86 bp modify : Ok
#
In verbose mode:
# perf test -v "bp modify"
62: x86 bp modify :
--- start ---
test child forked, pid 5161
rip 5950a0, bp_1 0x5950a0
in bp_1
rip 5950a0, bp_1 0x5950a0
in bp_1
test child finished with 0
---- end ----
x86 bp modify: Ok
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-6-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently we enable the breakpoint back only if the breakpoint
modification was successful. If it fails we can leave the breakpoint in
disabled state with attr->disabled == 0.
We can safely enable the breakpoint back for both the fail and success
paths by checking the bp->attr.disabled, which either holds the new
'requested' disabled state or the original breakpoint state.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-5-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Once the breakpoint was succesfully modified, the attr->disabled value
is in bp->attr.disabled. So there's no reason to set it again, removing
that.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We need to change the breakpoint even if the attr with new fields has
disabled set to true.
Current code prevents following user code to change the breakpoint
address:
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_1)
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_2)
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[7]), dr7)
The first PTRACE_POKEUSER creates the breakpoint with attr.disabled set
to true:
ptrace_set_breakpoint_addr(nr = 0)
struct perf_event *bp = t->ptrace_bps[nr];
ptrace_register_breakpoint(..., disabled = true)
ptrace_fill_bp_fields(..., disabled)
register_user_hw_breakpoint
So the second PTRACE_POKEUSER will be omitted:
ptrace_set_breakpoint_addr(nr = 0)
struct perf_event *bp = t->ptrace_bps[nr];
struct perf_event_attr attr = bp->attr;
modify_user_hw_breakpoint(bp, &attr)
if (!attr->disabled)
modify_user_hw_breakpoint_check
Reported-by: Milind Chabbi <chabbi.milind@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Almost all files in the kernel are either plain text or UTF-8 encoded. A
couple however are ISO_8859-1, usually just a few characters in a C
comments, for historic reasons.
This converts them all to UTF-8 for consistency.
Link: http://lkml.kernel.org/r/20180724111600.4158975-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Simon Horman <horms@verge.net.au> [IPVS portion]
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [IIO]
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Acked-by: Rob Herring <robh@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull core signal handling updates from Eric Biederman:
"It was observed that a periodic timer in combination with a
sufficiently expensive fork could prevent fork from every completing.
This contains the changes to remove the need for that restart.
This set of changes is split into several parts:
- The first part makes PIDTYPE_TGID a proper pid type instead
something only for very special cases. The part starts using
PIDTYPE_TGID enough so that in __send_signal where signals are
actually delivered we know if the signal is being sent to a a group
of processes or just a single process.
- With that prep work out of the way the logic in fork is modified so
that fork logically makes signals received while it is running
appear to be received after the fork completes"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
signal: Don't send signals to tasks that don't exist
signal: Don't restart fork when signals come in.
fork: Have new threads join on-going signal group stops
fork: Skip setting TIF_SIGPENDING in ptrace_init_task
signal: Add calculate_sigpending()
fork: Unconditionally exit if a fatal signal is pending
fork: Move and describe why the code examines PIDNS_ADDING
signal: Push pid type down into complete_signal.
signal: Push pid type down into __send_signal
signal: Push pid type down into send_signal
signal: Pass pid type into do_send_sig_info
signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
signal: Pass pid type into group_send_sig_info
signal: Pass pid and pid type into send_sigqueue
posix-timers: Noralize good_sigevent
signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
pid: Implement PIDTYPE_TGID
pids: Move the pgrp and session pid pointers from task_struct to signal_struct
kvm: Don't open code task_pid in kvm_vcpu_ioctl
pids: Compute task_tgid using signal->leader_pid
...
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of
a lot of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockde and the latency tracers
just get called directly (without using the trace events).
But because the original change cleaned up the code very nicely
we kept that, as well as the trace events for preempt and irqs
disabling, but they are limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not
allow them to be called in NMI context. Waiting till Paul makes
an NMI safe SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested
before the merge window opened.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCW3ruhRQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qiM7AP47NhYdSnCFCRUJfrt6PovXmQtuCHt3
c3QMoGGdvzh9YAEAqcSXwh7uLhpHUp1LjMAPkXdZVwNddf4zJQ1zyxQ+EAU=
=vgEr
-----END PGP SIGNATURE-----
Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of a lot
of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockdep and the latency tracers just
get called directly (without using the trace events). But because the
original change cleaned up the code very nicely we kept that, as well
as the trace events for preempt and irqs disabling, but they are
limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not allow
them to be called in NMI context. Waiting till Paul makes an NMI safe
SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested before
the merge window opened.
* tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
tracing: Fix SPDX format headers to use C++ style comments
tracing: Add SPDX License format tags to tracing files
tracing: Add SPDX License format to bpf_trace.c
blktrace: Add SPDX License format header
s390/ftrace: Add -mfentry and -mnop-mcount support
tracing: Add -mcount-nop option support
tracing: Avoid calling cc-option -mrecord-mcount for every Makefile
tracing: Handle CC_FLAGS_FTRACE more accurately
Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()
Uprobes: Simplify uprobe_register() body
tracepoints: Free early tracepoints after RCU is initialized
uprobes: Use synchronize_rcu() not synchronize_sched()
tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
ftrace: Remove unused pointer ftrace_swapper_pid
tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing/irqsoff: Handle preempt_count for different configs
tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing: irqsoff: Account for additional preempt_disable
trace: Use rcu_dereference_raw for hooks from trace-event subsystem
tracing/kprobes: Fix within_notrace_func() to check only notrace functions
...
A bunch of good stuff in here:
- Wire up support for qspinlock, replacing our trusty ticket lock code
- Add an IPI to flush_icache_range() to ensure that stale instructions
fetched into the pipeline are discarded along with the I-cache lines
- Support for the GCC "stackleak" plugin
- Support for restartable sequences, plus an arm64 port for the selftest
- Kexec/kdump support on systems booting with ACPI
- Rewrite of our syscall entry code in C, which allows us to zero the
GPRs on entry from userspace
- Support for chained PMU counters, allowing 64-bit event counters to be
constructed on current CPUs
- Ensure scheduler topology information is kept up-to-date with CPU
hotplug events
- Re-enable support for huge vmalloc/IO mappings now that the core code
has the correct hooks to use break-before-make sequences
- Miscellaneous, non-critical fixes and cleanups
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABCgAGBQJbbV41AAoJELescNyEwWM0WoEIALhrKtsIn6vqFlSs/w6aDuJL
cMWmFxjTaKLmIq2+cJIdFLOJ3CH80Pu9gB+nEv/k+cZdCTfUVKfRf28HTpmYWsht
bb4AhdHMC7yFW752BHk+mzJspeC8h/2Rm8wMuNVplZ3MkPrwo3vsiuJTofLhVL/y
BihlU3+5sfBvCYIsWnuEZIev+/I/s/qm1ASiqIcKSrFRZP6VTt5f9TC75vFI8seW
7yc3odKb0CArexB8yBjiPNziehctQF42doxQyL45hezLfWw4qdgHOSiwyiOMxEz9
Fwwpp8Tx33SKLNJgqoqYznGW9PhYJ7n2Kslv19uchJrEV+mds82vdDNaWRULld4=
=kQn6
-----END PGP SIGNATURE-----
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"A bunch of good stuff in here. Worth noting is that we've pulled in
the x86/mm branch from -tip so that we can make use of the core
ioremap changes which allow us to put down huge mappings in the
vmalloc area without screwing up the TLB. Much of the positive
diffstat is because of the rseq selftest for arm64.
Summary:
- Wire up support for qspinlock, replacing our trusty ticket lock
code
- Add an IPI to flush_icache_range() to ensure that stale
instructions fetched into the pipeline are discarded along with the
I-cache lines
- Support for the GCC "stackleak" plugin
- Support for restartable sequences, plus an arm64 port for the
selftest
- Kexec/kdump support on systems booting with ACPI
- Rewrite of our syscall entry code in C, which allows us to zero the
GPRs on entry from userspace
- Support for chained PMU counters, allowing 64-bit event counters to
be constructed on current CPUs
- Ensure scheduler topology information is kept up-to-date with CPU
hotplug events
- Re-enable support for huge vmalloc/IO mappings now that the core
code has the correct hooks to use break-before-make sequences
- Miscellaneous, non-critical fixes and cleanups"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (90 commits)
arm64: alternative: Use true and false for boolean values
arm64: kexec: Add comment to explain use of __flush_icache_range()
arm64: sdei: Mark sdei stack helper functions as static
arm64, kaslr: export offset in VMCOREINFO ELF notes
arm64: perf: Add cap_user_time aarch64
efi/libstub: Only disable stackleak plugin for arm64
arm64: drop unused kernel_neon_begin_partial() macro
arm64: kexec: machine_kexec should call __flush_icache_range
arm64: svc: Ensure hardirq tracing is updated before return
arm64: mm: Export __sync_icache_dcache() for xen-privcmd
drivers/perf: arm-ccn: Use devm_ioremap_resource() to map memory
arm64: Add support for STACKLEAK gcc plugin
arm64: Add stack information to on_accessible_stack
drivers/perf: hisi: update the sccl_id/ccl_id when MT is supported
arm64: fix ACPI dependencies
rseq/selftests: Add support for arm64
arm64: acpi: fix alignment fault in accessing ACPI
efi/arm: map UEFI memory map even w/o runtime services enabled
efi/arm: preserve early mapping of UEFI memory map longer for BGRT
drivers: acpi: add dependency of EFI for arm64
...
Add addition argument 'arch_uprobe' to uprobe_write_opcode().
We need this in later set of patches.
Link: http://lkml.kernel.org/r/20180809041856.1547-3-ravi.bangoria@linux.ibm.com
Reviewed-by: Song Liu <songliubraving@fb.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Simplify uprobe_register() function body and let __uprobe_register()
handle everything. Also move dependency functions around to avoid build
failures.
Link: http://lkml.kernel.org/r/20180809041856.1547-2-ravi.bangoria@linux.ibm.com
Reviewed-by: Song Liu <songliubraving@fb.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
It is useful to get the running time of a thread. Doing so in an
efficient manner can be important for performance of user applications.
Avoiding system calls in `clock_gettime` when handling
CLOCK_THREAD_CPUTIME_ID is important. Other clocks are handled in the
VDSO, but CLOCK_THREAD_CPUTIME_ID falls back on the system call.
CLOCK_THREAD_CPUTIME_ID is not handled in the VDSO since it would have
costs associated with maintaining updated user space accessible time
offsets. These offsets have to be updated everytime the a thread is
scheduled/descheduled. However, for programs regularly checking the
running time of a thread, this is a performance improvement.
This patch takes a middle ground, and adds support for cap_user_time an
optional feature of the perf_event API. This way costs are only
incurred when the perf_event api is enabled. This is done the same way
as it is in x86.
Ultimately this allows calculating the thread running time in userspace
on aarch64 as follows (adapted from perf_event_open manpage):
u32 seq, time_mult, time_shift;
u64 running, count, time_offset, quot, rem, delta;
struct perf_event_mmap_page *pc;
pc = buf; // buf is the perf event mmaped page as documented in the API.
if (pc->cap_usr_time) {
do {
seq = pc->lock;
barrier();
running = pc->time_running;
count = readCNTVCT_EL0(); // Read ARM hardware clock.
time_offset = pc->time_offset;
time_mult = pc->time_mult;
time_shift = pc->time_shift;
barrier();
} while (pc->lock != seq);
quot = (count >> time_shift);
rem = count & (((u64)1 << time_shift) - 1);
delta = time_offset + quot * time_mult +
((rem * time_mult) >> time_shift);
running += delta;
// running now has the current nanosecond level thread time.
}
Summary of changes in the patch:
For aarch64 systems, make arch_perf_update_userpage update the timing
information stored in the perf_event page. Requiring the following
calculations:
- Calculate the appropriate time_mult, and time_shift factors to convert
ticks to nano seconds for the current clock frequency.
- Adjust the mult and shift factors to avoid shift factors of 32 bits.
(possibly unnecessary)
- The time_offset userspace should apply when doing calculations:
negative the current sched time (now), because time_running and
time_enabled fields of the perf_event page have just been updated.
Toggle bits to appropriate values:
- Enable cap_user_time
Signed-off-by: Michael O'Farrell <micpof@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In function perf_event_parse_addr_filter(), the path::dentry of each struct
perf_addr_filter is left unassigned (as it should be) when the pattern
being parsed is related to kernel space. But in function
perf_addr_filter_match() the same dentries are given to d_inode() where
the value is not expected to be NULL, resulting in the following splat:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058
pc : perf_event_mmap+0x2fc/0x5a0
lr : perf_event_mmap+0x2c8/0x5a0
Process uname (pid: 2860, stack limit = 0x000000001cbcca37)
Call trace:
perf_event_mmap+0x2fc/0x5a0
mmap_region+0x124/0x570
do_mmap+0x344/0x4f8
vm_mmap_pgoff+0xe4/0x110
vm_mmap+0x2c/0x40
elf_map+0x60/0x108
load_elf_binary+0x450/0x12c4
search_binary_handler+0x90/0x290
__do_execve_file.isra.13+0x6e4/0x858
sys_execve+0x3c/0x50
el0_svc_naked+0x30/0x34
This patch is fixing the problem by introducing a new check in function
perf_addr_filter_match() to see if the filter's dentry is NULL.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: miklos@szeredi.hu
Cc: namhyung@kernel.org
Cc: songliubraving@fb.com
Fixes: 9511bce9fe ("perf/core: Fix bad use of igrab()")
Link: http://lkml.kernel.org/r/1531782831-1186-1-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vince reported the perf_fuzzer giving various unwinder warnings and
Josh reported:
> Deja vu. Most of these are related to perf PEBS, similar to the
> following issue:
>
> b8000586c9 ("perf/x86/intel: Cure bogus unwind from PEBS entries")
>
> This is basically the ORC version of that. setup_pebs_sample_data() is
> assembling a franken-pt_regs which ORC isn't happy about. RIP is
> inconsistent with some of the other registers (like RSP and RBP).
And where the previous unwinder only needed BP,SP ORC also requires
IP. But we cannot spoof IP because then the sample will get displaced,
entirely negating the point of PEBS.
So cure the whole thing differently by doing the unwind early; this
does however require a means to communicate we did the unwind early.
We (ab)use an unused sample_type bit for this, which we set on events
that fill out the data->callchain before the normal
perf_prepare_sample().
Debugged-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Everywhere except in the pid array we distinguish between a tasks pid and
a tasks tgid (thread group id). Even in the enumeration we want that
distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid
we almost have an implementation of PIDTYPE_TGID in struct signal_struct.
Add PIDTYPE_TGID as a first class member of the pid_type enumeration and
into the pids array. Then remove the __PIDTYPE_TGID special case and the
leader_pid in signal_struct.
The net size increase is just an extra pointer added to struct pid and
an extra pair of pointers of an hlist_node added to task_struct.
The effect on code maintenance is the removal of a number of special
cases today and the potential to remove many more special cases as
PIDTYPE_TGID gets used to it's fullest. The long term potential
is allowing zombie thread group leaders to exit, which will remove
a lot more special cases in the code.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Some of the comments in the perf events code use articles incorrectly,
using 'a' for words beginning with a vowel sound, where 'an' should be
used.
Signed-off-by: Tobias Tefke <tobias.tefke@tutanota.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: alexander.shishkin@linux.intel.com
Cc: jolsa@redhat.com
Cc: namhyung@kernel.org
Link: http://lkml.kernel.org/r/20180709105715.22938-1-tobias.tefke@tutanota.com
[ Fix a few more perf related 'a event' typo fixes from all around the kernel and tooling tree. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Remove the dance around old and new attributes. Just don't modify the
previous breakpoint at all until we have verified everything.
Original-patch-by: Andy Lutomirski <luto@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-13-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We soon won't be able to rely on bp->attr anymore to get the new
type of the modifying breakpoint because the new attributes are going
to be copied only once we successfully modified the breakpoint slot.
This will fix the current misdesigned layout where the new attr are
copied to the modifying breakpoint before we actually know if the
modification will be validated.
In order to prepare for that, allow modify_breakpoint_slot() to take
the new breakpoint type.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-12-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
All architectures have implemented it, we can now remove the poor weak
version.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-11-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We can't pass the breakpoint directly on arch_check_bp_in_kernelspace()
anymore because its architecture internal datas (struct arch_hw_breakpoint)
are not yet filled by the time we call the function, and most
implementation need this backend to be up to date. So arrange the
function to take the probing struct instead.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-3-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch_validate_hwbkpt_settings() mixes up attribute check and commit into
a single code entity. Therefore the validation may return an error due to
incorrect atributes while still leaving halfway modified architecture
breakpoint data.
This is harmless when we deal with a new breakpoint but it becomes a
problem when we modify an existing breakpoint.
Split attribute parse and commit to fix that. The architecture is
passed a "struct arch_hw_breakpoint" to fill on top of the new attr
and the core takes care about copying the backend data once it's fully
validated. The architectures then need to implement the new API.
Original-patch-by: Andy Lutomirski <luto@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Davidlohr Bueso
Stephane Eranian
Linus Torvalds
Jérôme Glisse
Ingo Molnar
Ravi Bangoria
Paul E. McKenney
Andrea Parri
Colin Ian King
Song Liu
Jiri Olsa
Peter Zijlstra
Reinette Chatre
Alexander Shishkin
Eric W. Biederman
Yabin Cui
Jiri Olsa
Arnd Bergmann
Michael O'Farrell
Mathieu Poirier
Tobias Tefke
Mathieu Malaterre
Frederic Weisbecker