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A mirror of the official Linux kernel repository just in case
d2753e6b48
Paul Menzel reported the following bug: > Enabling the undefined behavior sanitizer and building GNU/Linux 4.18-rc5+ > (with some unrelated commits) with GCC 8.1.0 from Debian Sid/unstable, the > warning below is shown. > > > [ 2.111913] > > ================================================================================ > > [ 2.111917] UBSAN: Undefined behaviour in arch/x86/events/amd/ibs.c:582:24 > > [ 2.111919] member access within null pointer of type 'struct perf_event' > > [ 2.111926] CPU: 0 PID: 144 Comm: udevadm Not tainted 4.18.0-rc5-00316-g4864b68cedf2 #104 > > [ 2.111928] Hardware name: ASROCK E350M1/E350M1, BIOS TIMELESS 01/01/1970 > > [ 2.111930] Call Trace: > > [ 2.111943] dump_stack+0x55/0x89 > > [ 2.111949] ubsan_epilogue+0xb/0x33 > > [ 2.111953] handle_null_ptr_deref+0x7f/0x90 > > [ 2.111958] __ubsan_handle_type_mismatch_v1+0x55/0x60 > > [ 2.111964] perf_ibs_handle_irq+0x596/0x620 The code dereferences event before checking the STARTED bit. Patch below should cure the issue. The warning should not trigger, if I analyzed the thing correctly. (And Paul's testing confirms this.) Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> Tested-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Menzel <pmenzel+linux-x86@molgen.mpg.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1807200958390.1580@nanos.tec.linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.