Date: Wed, 4 Dec 2019 09:21:00 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r355385 - stable/12/sys/kern Message-ID: <201912040921.xB49L0Mx079338@repo.freebsd.org>
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Author: kib Date: Wed Dec 4 09:21:00 2019 New Revision: 355385 URL: https://svnweb.freebsd.org/changeset/base/355385 Log: MFC r355146: Ease the life of PT_TO_SCE/PT_TO_SCX users when debuggee sleeps in sigsuspend(2)/sig{timed,}wait(2). Modified: stable/12/sys/kern/kern_sig.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/kern/kern_sig.c ============================================================================== --- stable/12/sys/kern/kern_sig.c Wed Dec 4 09:18:32 2019 (r355384) +++ stable/12/sys/kern/kern_sig.c Wed Dec 4 09:21:00 2019 (r355385) @@ -65,6 +65,7 @@ __FBSDID("$FreeBSD$"); #include <sys/namei.h> #include <sys/proc.h> #include <sys/procdesc.h> +#include <sys/ptrace.h> #include <sys/posix4.h> #include <sys/pioctl.h> #include <sys/racct.h> @@ -1252,11 +1253,13 @@ kern_sigtimedwait(struct thread *td, sigset_t waitset, int error, sig, timo, timevalid = 0; struct timespec rts, ets, ts; struct timeval tv; + bool traced; p = td->td_proc; error = 0; ets.tv_sec = 0; ets.tv_nsec = 0; + traced = false; if (timeout != NULL) { if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { @@ -1309,6 +1312,11 @@ kern_sigtimedwait(struct thread *td, sigset_t waitset, timo = 0; } + if (traced) { + error = EINTR; + break; + } + error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo); if (timeout != NULL) { @@ -1320,6 +1328,16 @@ kern_sigtimedwait(struct thread *td, sigset_t waitset, error = 0; } } + + /* + * If PTRACE_SCE or PTRACE_SCX were set after + * userspace entered the syscall, return spurious + * EINTR after wait was done. Only do this as last + * resort after rechecking for possible queued signals + * and expired timeouts. + */ + if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0) + traced = true; } new_block = saved_mask; @@ -1532,6 +1550,14 @@ kern_sigsuspend(struct thread *td, sigset_t mask) has_sig += postsig(sig); } mtx_unlock(&p->p_sigacts->ps_mtx); + + /* + * If PTRACE_SCE or PTRACE_SCX were set after + * userspace entered the syscall, return spurious + * EINTR. + */ + if ((p->p_ptevents & PTRACE_SYSCALL) != 0) + has_sig += 1; } PROC_UNLOCK(p); td->td_errno = EINTR;
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