1. 24 Jul, 2018 1 commit
    • Thomas Gleixner's avatar
      perf/x86/amd/ibs: Don't access non-started event · d2753e6b
      Thomas Gleixner authored
      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: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
      Tested-by: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
      Signed-off-by: default avatarThomas 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.deSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      d2753e6b
  2. 22 Jul, 2018 8 commits
  3. 21 Jul, 2018 12 commits
  4. 20 Jul, 2018 17 commits
  5. 19 Jul, 2018 2 commits