Date: Tue, 10 Jan 2017 19:27:12 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 215826] C++ program signal handlers not called Message-ID: <bug-215826-8-4EGG4dDss7@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-215826-8@https.bugs.freebsd.org/bugzilla/> References: <bug-215826-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D215826 --- Comment #6 from commit-hook@freebsd.org --- A commit references this bug: Author: kib Date: Tue Jan 10 19:26:55 UTC 2017 New revision: 311886 URL: https://svnweb.freebsd.org/changeset/base/311886 Log: Fix acquisition of nested write compat rtld locks. Obtaining compat rtld lock in write mode sets process signal mask to block all signals. Previous mask is stored in the global variable oldsigmask. If a lock is write-locked while another lock is already write-locked, oldsigmask is overwritten by the total mask and on the last unlock, all signals except traps appear to be blocked. Fix this by counting the write-lock nested level, and only storing to oldsigmask/restoring from it at the outermost level. Masking signals disables involuntary preemption for libc_r, and there could be no voluntary context switches in the locked code (dl_iterate_phdr(3) keeps a lock around user callback, but it was added long after libc_r was renounced). Due to this, remembering the level in the global variable after the lock is obtained should be safe, because no two libc_r threads can acquire different write locks in parallel. PR: 215826 Reported by: kami Tested by: yamagi@yamagi.org (previous version) To be reviewed by: kan Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Changes: head/libexec/rtld-elf/rtld_lock.c --=20 You are receiving this mail because: You are the assignee for the bug.=
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