Messages in this thread Patch in this message | | | Date | Wed, 6 Jun 2012 09:02:09 -0700 | From | tip-bot for Arun Sharma <> | Subject | [tip:perf/core] perf/x86: Allow multiple stacks |
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Commit-ID: 302fa4b58ac754a6da13f4f5546f710fecc3b945 Gitweb: http://git.kernel.org/tip/302fa4b58ac754a6da13f4f5546f710fecc3b945 Author: Arun Sharma <asharma@fb.com> AuthorDate: Fri, 20 Apr 2012 15:41:33 -0700 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 6 Jun 2012 17:07:58 +0200
perf/x86: Allow multiple stacks
Without this patch, applications with two different stack regions (eg: native stack vs JIT stack) get truncated callchains even when RBP chaining is present. GDB shows proper stack traces and the frame pointer chaining is intact.
This patch disables the (fp < RSP) check, hoping that other checks in the code save the day for us. In our limited testing, this didn't seem to break anything.
In the long term, we could potentially have userspace advise the kernel on the range of valid stack addresses, so we don't spend a lot of time unwinding from bogus addresses.
Signed-off-by: Arun Sharma <asharma@fb.com> CC: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-perf-users@vger.kernel.org Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1334961696-19580-2-git-send-email-asharma@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/cpu/perf_event.c | 6 ------ 1 files changed, 0 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index cb60838..e78bc25 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1781,9 +1781,6 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry) if (bytes != sizeof(frame)) break; - if (fp < compat_ptr(regs->sp)) - break; - perf_callchain_store(entry, frame.return_address); fp = compat_ptr(frame.next_frame); } @@ -1827,9 +1824,6 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) if (bytes != sizeof(frame)) break; - if ((unsigned long)fp < regs->sp) - break; - perf_callchain_store(entry, frame.return_address); fp = frame.next_frame; }
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