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| author | Stephane Eranian <eranian@google.com> | 2022-09-28 21:40:42 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-09-29 13:20:56 +0300 |
| commit | 117ceeb1f4f87331e45a77e71f18303d15ec882e (patch) | |
| tree | 31299bdd4bd3ac6b5e79e78b1617315d68e57dc8 /arch/x86/events | |
| parent | cfef80bad4cf79cdc964a53c98254dfa462be83f (diff) | |
| download | linux-117ceeb1f4f87331e45a77e71f18303d15ec882e.tar.xz | |
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
Diffstat (limited to 'arch/x86/events')
| -rw-r--r-- | arch/x86/events/utils.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/events/utils.c b/arch/x86/events/utils.c index 5f5617afde79..76b1f8bb0fd5 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; |