1. 25 Jul, 2018 1 commit
    • Peter Zijlstra's avatar
      perf/x86/intel: Fix unwind errors from PEBS entries (mk-II) · 6cbc304f
      Peter Zijlstra authored
      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:
      >
      >   b8000586 ("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: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Reported-by: default avatarVince Weaver <vincent.weaver@maine.edu>
      Tested-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Tested-by: default avatarPrashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
      Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
      6cbc304f
  2. 24 Jul, 2018 2 commits
    • Ananth N Mavinakayanahalli's avatar
      MAINTAINERS: Add Naveen N. Rao as kprobes co-maintainer · 4799f685
      Ananth N Mavinakayanahalli authored
      Naveen has been contributing consistently reviewing and hardening
      kprobes for some time now. I have not been able to do the same due
      to other commitments.
      Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
      Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: akpm@linux-foundation.org
      Cc: mhiramat@kernel.org
      Link: http://lkml.kernel.org/r/153180735790.1914.15547706781664285286.stgit@thinktuxSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      4799f685
    • 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
  3. 22 Jul, 2018 8 commits
  4. 21 Jul, 2018 12 commits
  5. 20 Jul, 2018 17 commits