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| author | Marco Elver <[email protected]> | 2022-01-31 10:34:07 +0000 |
|---|---|---|
| committer | Peter Zijlstra <[email protected]> | 2022-02-02 12:11:40 +0000 |
| commit | ddecd22878601a606d160680fa85802b75d92eb6 (patch) | |
| tree | e3e3e3e0d39ced09c898006b35437ad933c52fe8 /lib/test_overflow.c | |
| parent | selftests/perf_events: Test modification of perf_event_attr::sig_data (diff) | |
| download | kernel-ddecd22878601a606d160680fa85802b75d92eb6.tar.gz kernel-ddecd22878601a606d160680fa85802b75d92eb6.zip | |
perf: uapi: Document perf_event_attr::sig_data truncation on 32 bit architectures
Due to the alignment requirements of siginfo_t, as described in
3ddb3fd8cdb0 ("signal, perf: Fix siginfo_t by avoiding u64 on 32-bit
architectures"), siginfo_t::si_perf_data is limited to an unsigned long.
However, perf_event_attr::sig_data is an u64, to avoid having to deal
with compat conversions. Due to being an u64, it may not immediately be
clear to users that sig_data is truncated on 32 bit architectures.
Add a comment to explicitly point this out, and hopefully help some
users save time by not having to deduce themselves what's happening.
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Dmitry Vyukov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Diffstat (limited to 'lib/test_overflow.c')
0 files changed, 0 insertions, 0 deletions