285a54efe3
ftracetest multiple_kprobes.tc testcase hits the following NULL pointer
exception:
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 800000007bf60067 P4D 800000007bf60067 PUD 7bf5f067 PMD 0
Oops: 0000 [#1] PREEMPT SMP PTI
RIP: 0010:poke_int3_handler+0x39/0x100
Call Trace:
<IRQ>
do_int3+0xd/0xf0
int3+0x42/0x50
RIP: 0010:sched_clock+0x6/0x10
poke_int3_handler+0x39 was alternatives:958:
static inline void *text_poke_addr(struct text_poke_loc *tp)
{
return _stext + tp->rel_addr; <------ Here is line #958
}
This seems to be caused by tp (bp_patching.vec) being NULL but
bp_patching.nr_entries != 0. There is a small chance for this
to happen, because we have no synchronization between the zeroing
of bp_patching.nr_entries and before clearing bp_patching.vec.
Steve suggested we could fix this by adding sync_core(), because int3
is done with interrupts disabled, and the on_each_cpu() requires
all CPUs to have had their interrupts enabled.
[ mingo: Edited the comments and the changelog. ]
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.