Sergey Senozhatsky 656d61ce96 lib/ratelimit.c: use deferred printk() version ... printk_ratelimit() invokes ___ratelimit() which may invoke a normal printk() (pr_warn() in this particular case) to warn about suppressed output. Given that printk_ratelimit() may be called from anywhere, that pr_warn() is dangerous - it may end up deadlocking the system. Fix ___ratelimit() by using deferred printk(). Sasha reported the following lockdep error: : Unregister pv shared memory for cpu 8 : select_fallback_rq: 3 callbacks suppressed : process 8583 (trinity-c78) no longer affine to cpu8 : : ====================================================== : WARNING: possible circular locking dependency detected : 4.14.0-rc2-next-20170927+ #252 Not tainted : ------------------------------------------------------ : migration/8/62 is trying to acquire lock: : (&port_lock_key){-.-.}, at: serial8250_console_write() : : but task is already holding lock: : (&rq->lock){-.-.}, at: sched_cpu_dying() : : which lock already depends on the new lock. : : : the existing dependency chain (in reverse order) is: : : -> #3 (&rq->lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock() : task_fork_fair() : sched_fork() : copy_process.part.31() : _do_fork() : kernel_thread() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #2 (&p->pi_lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : try_to_wake_up() : default_wake_function() : woken_wake_function() : __wake_up_common() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #1 (&tty->write_wait){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #0 (&port_lock_key){-.-.}: : check_prev_add() : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : serial8250_console_write() : univ8250_console_write() : console_unlock() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : cpuhp_invoke_callback() : take_cpu_down() : multi_cpu_stop() : cpu_stopper_thread() : smpboot_thread_fn() : kthread() : ret_from_fork() : : other info that might help us debug this: : : Chain exists of: : &port_lock_key --> &p->pi_lock --> &rq->lock : : Possible unsafe locking scenario: : : CPU0 CPU1 : ---- ---- : lock(&rq->lock); : lock(&p->pi_lock); : lock(&rq->lock); : lock(&port_lock_key); : : *** DEADLOCK *** : : 4 locks held by migration/8/62: : #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying() : #1: (&rq->lock){-.-.}, at: sched_cpu_dying() : #2: (printk_ratelimit_state.lock){....}, at: ___ratelimit() : #3: (console_lock){+.+.}, at: vprintk_emit() : : stack backtrace: : CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ #252 : Call Trace: : dump_stack() : print_circular_bug() : check_prev_add() : ? add_lock_to_list.isra.26() : ? check_usage() : ? kvm_clock_read() : ? kvm_sched_clock_read() : ? sched_clock() : ? check_preemption_disabled() : __lock_acquire() : ? __lock_acquire() : ? add_lock_to_list.isra.26() : ? debug_check_no_locks_freed() : ? memcpy() : lock_acquire() : ? serial8250_console_write() : _raw_spin_lock_irqsave() : ? serial8250_console_write() : serial8250_console_write() : ? serial8250_start_tx() : ? lock_acquire() : ? memcpy() : univ8250_console_write() : console_unlock() : ? __down_trylock_console_sem() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ? show_regs_print_info() : ? lock_acquire() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : ? sched_cpu_starting() : ? rcutree_dying_cpu() : ? sched_cpu_starting() : cpuhp_invoke_callback() : ? cpu_disable_common() : take_cpu_down() : ? trace_hardirqs_off_caller() : ? cpuhp_invoke_callback() : multi_cpu_stop() : ? __this_cpu_preempt_check() : ? cpu_stop_queue_work() : cpu_stopper_thread() : ? cpu_stop_create() : smpboot_thread_fn() : ? sort_range() : ? schedule() : ? __kthread_parkme() : kthread() : ? sort_range() : ? kthread_create_on_node() : ret_from_fork() : process 9121 (trinity-c78) no longer affine to cpu8 : smpboot: CPU 8 is now offline Link: http://lkml.kernel.org/r/20170928120405.18273-1-sergey.senozhatsky@gmail.com Fixes: 6b1d174b0c ("ratelimit: extend to print suppressed messages on release") Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Sasha Levin <levinsasha928@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Borislav Petkov <bp@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-10-03 17:54:26 -07:00
..
842	…
fonts	…
lz4	lib/lz4: make arrays static const, reduces object code size	2017-10-03 17:54:25 -07:00
lzo	…
mpi	…
raid6	…
reed_solomon	…
xz	…
zlib_deflate	…
zlib_inflate	…
zstd	…
.gitignore	…
Kconfig	Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2017-09-14 17:30:49 -07:00
Kconfig.debug	parisc: Fix too large frame size warnings	2017-09-22 19:46:07 +02:00
Kconfig.kasan	…
Kconfig.kgdb	…
Kconfig.kmemcheck	…
Kconfig.ubsan	…
Makefile	Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2017-09-14 17:30:49 -07:00
argv_split.c	…
asn1_decoder.c	…
assoc_array.c	…
atomic64.c	…
atomic64_test.c	…
audit.c	…
bcd.c	…
bch.c	…
bitmap.c	lib/bitmap.c: make bitmap_parselist() thread-safe and much faster	2017-09-08 18:26:49 -07:00
bitrev.c	…
bsearch.c	…
btree.c	…
bug.c	…
build_OID_registry	…
bust_spinlocks.c	…
chacha20.c	…
check_signature.c	…
checksum.c	…
clz_ctz.c	…
clz_tab.c	…
cmdline.c	lib/cmdline.c: remove meaningless comment	2017-09-08 18:26:49 -07:00
compat_audit.c	…
cordic.c	…
cpu_rmap.c	…
cpumask.c	cpumask: make cpumask_next() out-of-line	2017-09-08 18:26:51 -07:00
crc-ccitt.c	…
crc-itu-t.c	…
crc-t10dif.c	…
crc4.c	…
crc7.c	…
crc8.c	…
crc16.c	…
crc32.c	…
crc32defs.h	…
crc32test.c	…
ctype.c	…
debug_info.c	…
debug_locks.c	…
debugobjects.c	…
dec_and_lock.c	…
decompress.c	…
decompress_bunzip2.c	…
decompress_inflate.c	…
decompress_unlz4.c	…
decompress_unlzma.c	…
decompress_unlzo.c	…
decompress_unxz.c	…
devres.c	…
digsig.c	…
div64.c	…
dma-debug.c	…
dma-noop.c	…
dma-virt.c	…
dump_stack.c	…
dynamic_debug.c	…
dynamic_queue_limits.c	…
earlycpio.c	…
errseq.c	…
extable.c	…
fault-inject.c	…
fdt.c	…
fdt_empty_tree.c	…
fdt_ro.c	…
fdt_rw.c	…
fdt_strerror.c	…
fdt_sw.c	…
fdt_wip.c	…
find_bit.c	…
flex_array.c	…
flex_proportions.c	…
gcd.c	…
gen_crc32table.c	…
genalloc.c	…
glob.c	…
globtest.c	…
hexdump.c	lib/hexdump.c: return -EINVAL in case of error in hex2bin()	2017-09-08 18:26:49 -07:00
hweight.c	…
idr.c	lib/idr.c: fix comment for idr_replace()	2017-10-03 17:54:25 -07:00
inflate.c	…
int_sqrt.c	…
interval_tree.c	…
interval_tree_test.c	lib/interval_tree: fast overlap detection	2017-09-08 18:26:49 -07:00
iomap.c	…
iomap_copy.c	…
iommu-common.c	…
iommu-helper.c	…
ioremap.c	…
iov_iter.c	iov_iter: fix page_copy_sane for compound pages	2017-09-20 23:27:48 -04:00
irq_poll.c	…
irq_regs.c	…
is_single_threaded.c	…
jedec_ddr_data.c	…
kasprintf.c	…
kfifo.c	…
klist.c	…
kobject.c	…
kobject_uevent.c	driver core: suppress sending MODALIAS in UNBIND uevents	2017-09-18 16:48:33 +02:00
kstrtox.c	…
kstrtox.h	…
lcm.c	…
libcrc32c.c	…
list_debug.c	…
list_sort.c	…
llist.c	…
locking-selftest-hardirq.h	…
locking-selftest-mutex.h	…
locking-selftest-rlock-hardirq.h	…
locking-selftest-rlock-softirq.h	…
locking-selftest-rlock.h	…
locking-selftest-rsem.h	…
locking-selftest-rtmutex.h	…
locking-selftest-softirq.h	…
locking-selftest-spin-hardirq.h	…
locking-selftest-spin-softirq.h	…
locking-selftest-spin.h	…
locking-selftest-wlock-hardirq.h	…
locking-selftest-wlock-softirq.h	…
locking-selftest-wlock.h	…
locking-selftest-wsem.h	…
locking-selftest.c	…
lockref.c	…
lru_cache.c	…
memory-notifier-error-inject.c	…
memweight.c	…
net_utils.c	…
netdev-notifier-error-inject.c	…
nlattr.c	…
nmi_backtrace.c	…
nodemask.c	…
notifier-error-inject.c	…
notifier-error-inject.h	…
of-reconfig-notifier-error-inject.c	…
oid_registry.c	lib/oid_registry.c: X.509: fix the buffer overflow in the utility function for OID string	2017-09-08 18:26:49 -07:00
once.c	…
parman.c	…
parser.c	…
pci_iomap.c	…
percpu-refcount.c	…
percpu_counter.c	…
percpu_ida.c	…
percpu_test.c	…
plist.c	…
pm-notifier-error-inject.c	…
prime_numbers.c	…
radix-tree.c	radix-tree: must check __radix_tree_preload() return value	2017-09-08 18:26:49 -07:00
random32.c	…
ratelimit.c	lib/ratelimit.c: use deferred printk() version	2017-10-03 17:54:26 -07:00
rational.c	…
rbtree.c	rbtree: add some additional comments for rebalancing cases	2017-09-08 18:26:48 -07:00
rbtree_test.c	lib/rbtree_test.c: support rb_root_cached	2017-09-08 18:26:48 -07:00
reciprocal_div.c	…
refcount.c	…
rhashtable.c	rhashtable: Documentation tweak	2017-09-19 15:18:33 -07:00
sbitmap.c	…
scatterlist.c	…
seq_buf.c	…
sg_pool.c	…
sg_split.c	…
sha1.c	…
show_mem.c	…
siphash.c	…
smp_processor_id.c	…
sort.c	…
stackdepot.c	…
stmp_device.c	…
string.c	lib/string.c: check for kmalloc() failure	2017-09-08 18:26:49 -07:00
string_helpers.c	mm: treewide: remove GFP_TEMPORARY allocation flag	2017-09-13 18:53:16 -07:00
strncpy_from_user.c	…
strnlen_user.c	…
swiotlb.c	…
syscall.c	…
test-kstrtox.c	…
test-string_helpers.c	…
test_bitmap.c	lib/test_bitmap.c: use ULL suffix for 64-bit constants	2017-09-13 18:53:15 -07:00
test_bpf.c	…
test_debug_virtual.c	lib: add test module for CONFIG_DEBUG_VIRTUAL	2017-09-08 18:26:49 -07:00
test_firmware.c	…
test_hash.c	…
test_hexdump.c	…
test_kasan.c	…
test_kmod.c	test_kmod: flip INT checks to be consistent	2017-09-08 18:26:50 -07:00
test_list_sort.c	…
test_module.c	…
test_parman.c	…
test_printf.c	…
test_rhashtable.c	…
test_siphash.c	…
test_sort.c	…
test_static_key_base.c	…
test_static_keys.c	…
test_sysctl.c	…
test_user_copy.c	…
test_uuid.c	…
textsearch.c	…
timerqueue.c	…
ts_bm.c	…
ts_fsm.c	…
ts_kmp.c	…
ubsan.c	…
ubsan.h	…
ucs2_string.c	…
usercopy.c	…
uuid.c	…
vsprintf.c	…
win_minmax.c	…
xxhash.c	…