* tip-bot2 for Thorsten Blum <tip-bot2@xxxxxxxxxxxxx> wrote: > The following commit has been merged into the perf/core branch of tip: > > Commit-ID: 077dcef270361089c322a969b792438b33cfb479 > Gitweb: https://git.kernel.org/tip/077dcef270361089c322a969b792438b33cfb479 > Author: Thorsten Blum <thorsten.blum@xxxxxxxxx> > AuthorDate: Tue, 04 Mar 2025 19:30:57 +01:00 > Committer: Ingo Molnar <mingo@xxxxxxxxxx> > CommitterDate: Tue, 04 Mar 2025 19:58:01 +01:00 > > perf/x86: Annotate struct bts_buffer with __counted_by() > > Add the __counted_by() compiler attribute to the flexible array member > buf to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and > CONFIG_FORTIFY_SOURCE. > > Use struct_size() to calculate the number of bytes to allocate for a new > bts_buffer. Compared to offsetof(), struct_size() has additional > compile-time checks (e.g., __must_be_array()). > > No functional changes intended. > > Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx> > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Link: https://lore.kernel.org/r/20250304183056.78920-2-thorsten.blum@xxxxxxxxx > --- > arch/x86/events/intel/bts.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c > index 8e09319..debfc18 100644 > --- a/arch/x86/events/intel/bts.c > +++ b/arch/x86/events/intel/bts.c > @@ -58,7 +58,7 @@ struct bts_buffer { > local_t head; > unsigned long end; > void **data_pages; > - struct bts_phys buf[]; > + struct bts_phys buf[] __counted_by(nr_bufs); > }; > > static struct pmu bts_pmu; > @@ -101,7 +101,7 @@ bts_buffer_setup_aux(struct perf_event *event, void **pages, > if (overwrite && nbuf > 1) > return NULL; Actually, on a second thought: > - buf = kzalloc_node(offsetof(struct bts_buffer, buf[nbuf]), GFP_KERNEL, node); > + buf = kzalloc_node(struct_size(buf, buf, nbuf), GFP_KERNEL, node); Firstly, in what world is 'buf, buf' more readable? One is a member of a structure, the other is the name of the structure - and they match, which shows that this function's naming conventions are a mess. Which should be fixed first ... I'm also not sure the code is correct ... So I zapped this commit from tip:perf/core. Thanks, Ingo
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