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 <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20220131103407.1971678-3-elver@google.com
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| .. | ||
| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kunit | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| vdso | ||
| video | ||
| xen | ||