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From: "fweimer at redhat dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug libc/31479] Missing #include <sys/rseq.h> in sched_getcpu.c may result in a loss of rseq acceleration Date: Mon, 18 Mar 2024 11:32:32 +0000 [thread overview] Message-ID: <bug-31479-131-iO8kCMDvbX@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-31479-131@http.sourceware.org/bugzilla/> https://sourceware.org/bugzilla/show_bug.cgi?id=31479 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |2.40 Resolution|--- |FIXED Status|ASSIGNED |RESOLVED --- Comment #2 from Florian Weimer <fweimer at redhat dot com> --- Fixed for 2.40 via: commit 7a76f218677d149d8b7875b336722108239f7ee9 Author: Florian Weimer <fweimer@redhat.com> Date: Fri Mar 15 19:08:24 2024 +0100 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> -- You are receiving this mail because: You are on the CC list for the bug.
prev parent reply other threads:[~2024-03-18 11:32 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-13 10:28 [Bug libc/31479] New: " fweimer at redhat dot com 2024-03-13 10:28 ` [Bug libc/31479] " fweimer at redhat dot com 2024-03-13 12:24 ` fweimer at redhat dot com 2024-03-18 11:31 ` fweimer at redhat dot com 2024-03-18 11:32 ` fweimer at redhat dot com [this message]
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