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| author | Florian Weimer <fweimer@redhat.com> | 2024-03-15 19:08:24 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2024-03-15 19:08:24 +0100 |
| commit | 7a76f218677d149d8b7875b336722108239f7ee9 (patch) | |
| tree | 15fb0b3f92de546353acc3a1e7d641f24cdf9ec4 /sysdeps/unix/bsd/gtty.c | |
| parent | 73c26018ed0ecd9c807bb363cc2c2ab4aca66a82 (diff) | |
| download | glibc-7a76f218677d149d8b7875b336722108239f7ee9.tar.gz glibc-7a76f218677d149d8b7875b336722108239f7ee9.tar.xz glibc-7a76f218677d149d8b7875b336722108239f7ee9.zip | |
linux: Use rseq area unconditionally in sched_getcpu (bug 31479)
Originally, nptl/descr.h included <sys/rseq.h>, but we removed that
in commit 2c6b4b272e6b4d07303af25709051c3e96288f2d ("nptl:
Unconditionally use a 32-byte rseq area"). After that, it was
not ensured that the RSEQ_SIG macro was defined during sched_getcpu.c
compilation that provided a definition. This commit always checks
the rseq area for CPU number information before using the other
approaches.
This adds an unnecessary (but well-predictable) branch on
architectures which do not define RSEQ_SIG, but its cost is small
compared to the system call. Most architectures that have vDSO
acceleration for getcpu also have rseq support.
Fixes: 2c6b4b272e6b4d07303af25709051c3e96288f2d
Fixes: 1d350aa06091211863e41169729cee1bca39f72f
Reviewed-by: Arjun Shankar <arjun@redhat.com>
Diffstat (limited to 'sysdeps/unix/bsd/gtty.c')
0 files changed, 0 insertions, 0 deletions