Messages in this thread Patch in this message | | | Date | Fri, 30 Sep 2022 09:31:01 -0000 | From | "tip-bot2 for Stephane Eranian" <> | Subject | [tip: perf/core] perf/x86/utils: Fix uninitialized var in get_branch_type() |
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The following commit has been merged into the perf/core branch of tip:
Commit-ID: 117ceeb1f4f87331e45a77e71f18303d15ec882e Gitweb: https://git.kernel.org/tip/117ceeb1f4f87331e45a77e71f18303d15ec882e Author: Stephane Eranian <eranian@google.com> AuthorDate: Wed, 28 Sep 2022 11:40:42 -07:00 Committer: Peter Zijlstra <peterz@infradead.org> CommitterDate: Thu, 29 Sep 2022 12:20:56 +02:00
perf/x86/utils: Fix uninitialized var in get_branch_type()
offset is passed as a pointer and on certain call path is not set by the function. If the caller does not re-initialize offset between calls, value could be inherited between calls. Prevent this by initializing offset on each call.
This impacts the code in amd_pmu_lbr_filter() which does:
for(i=0; ...) { ret = get_branch_type_fused(..., &offset); if (offset) lbr_entries[i].from += offset; }
Fixes: df3e9612f758 ("perf/x86: Make branch classifier fusion-aware") Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sandipan Das <sandipan.das@amd.com> Link: https://lore.kernel.org/r/20220928184043.408364-2-eranian@google.com --- arch/x86/events/utils.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/x86/events/utils.c b/arch/x86/events/utils.c index 5f5617a..76b1f8b 100644 --- a/arch/x86/events/utils.c +++ b/arch/x86/events/utils.c @@ -94,6 +94,10 @@ static int get_branch_type(unsigned long from, unsigned long to, int abort, u8 buf[MAX_INSN_SIZE]; int is64 = 0; + /* make sure we initialize offset */ + if (offset) + *offset = 0; + to_plm = kernel_ip(to) ? X86_BR_KERNEL : X86_BR_USER; from_plm = kernel_ip(from) ? X86_BR_KERNEL : X86_BR_USER;
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