diff options
| author | riastradh <riastradh@NetBSD.org> | 2022-06-29 22:27:01 +0000 |
|---|---|---|
| committer | riastradh <riastradh@NetBSD.org> | 2022-06-29 22:27:01 +0000 |
| commit | 1d15b657dfc539a24f6ceeb6894184bf3bc42d64 (patch) | |
| tree | cc8e254dc68f71cd42c57f80f290b2f7b0362558 /sys | |
| parent | 4f46ee441c5fd0e1667f385005b453dca450871b (diff) | |
sleepq(9): Pass syncobj through to sleepq_block.
Previously the usage pattern was:
sleepq_enter(sq, l, lock); // locks l
...
sleepq_enqueue(sq, ..., sobj, ...); // assumes l locked, sets l_syncobj
... (*)
sleepq_block(...); // unlocks l
As long as l remains locked from sleepq_enter to sleepq_block,
l_syncobj is stable, and sleepq_block uses it via ktrcsw to determine
whether the sleep is on a mutex in order to avoid creating ktrace
context-switch records (which involves allocation which is forbidden
in softint context, while taking and even sleeping for a mutex is
allowed).
However, in turnstile_block, the logic at (*) also involves
turnstile_lendpri, which sometimes unlocks and relocks l. At that
point, another thread can swoop in and sleepq_remove l, which sets
l_syncobj to sched_syncobj. If that happens, ktrcsw does what is
forbidden -- tries to allocate a ktrace record for the context
switch.
As an optimization, sleepq_block or turnstile_block could stop early
if it detects that l_syncobj doesn't match -- we've already been
requested to wake up at this point so there's no need to mi_switch.
(And then it would be unnecessary to pass the syncobj through
sleepq_block, because l_syncobj would remain stable.) But I'll leave
that to another change.
Reported-by: syzbot+8b9d7b066c32dbcdc63b@syzkaller.appspotmail.com
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/kern/kern_condvar.c | 12 | ||||
| -rw-r--r-- | sys/kern/kern_sleepq.c | 7 | ||||
| -rw-r--r-- | sys/kern/kern_synch.c | 10 | ||||
| -rw-r--r-- | sys/kern/kern_timeout.c | 6 | ||||
| -rw-r--r-- | sys/kern/kern_turnstile.c | 6 | ||||
| -rw-r--r-- | sys/kern/sys_lwp.c | 6 | ||||
| -rw-r--r-- | sys/kern/sys_select.c | 6 | ||||
| -rw-r--r-- | sys/sys/sleepq.h | 4 |
8 files changed, 28 insertions, 29 deletions
diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c index f5cc99a166c..a4f8b60341a 100644 --- a/sys/kern/kern_condvar.c +++ b/sys/kern/kern_condvar.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_condvar.c,v 1.53 2020/11/01 20:55:15 christos Exp $ */ +/* $NetBSD: kern_condvar.c,v 1.54 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2006, 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc. @@ -34,7 +34,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_condvar.c,v 1.53 2020/11/01 20:55:15 christos Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_condvar.c,v 1.54 2022/06/29 22:27:01 riastradh Exp $"); #include <sys/param.h> #include <sys/systm.h> @@ -171,7 +171,7 @@ cv_wait(kcondvar_t *cv, kmutex_t *mtx) KASSERT(mutex_owned(mtx)); cv_enter(cv, mtx, l, false); - (void)sleepq_block(0, false); + (void)sleepq_block(0, false, &cv_syncobj); mutex_enter(mtx); } @@ -192,7 +192,7 @@ cv_wait_sig(kcondvar_t *cv, kmutex_t *mtx) KASSERT(mutex_owned(mtx)); cv_enter(cv, mtx, l, true); - error = sleepq_block(0, true); + error = sleepq_block(0, true, &cv_syncobj); mutex_enter(mtx); return error; } @@ -215,7 +215,7 @@ cv_timedwait(kcondvar_t *cv, kmutex_t *mtx, int timo) KASSERT(mutex_owned(mtx)); cv_enter(cv, mtx, l, false); - error = sleepq_block(timo, false); + error = sleepq_block(timo, false, &cv_syncobj); mutex_enter(mtx); return error; } @@ -240,7 +240,7 @@ cv_timedwait_sig(kcondvar_t *cv, kmutex_t *mtx, int timo) KASSERT(mutex_owned(mtx)); cv_enter(cv, mtx, l, true); - error = sleepq_block(timo, true); + error = sleepq_block(timo, true, &cv_syncobj); mutex_enter(mtx); return error; } diff --git a/sys/kern/kern_sleepq.c b/sys/kern/kern_sleepq.c index 50a5e6b25e2..23735578250 100644 --- a/sys/kern/kern_sleepq.c +++ b/sys/kern/kern_sleepq.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_sleepq.c,v 1.72 2022/06/29 22:10:43 riastradh Exp $ */ +/* $NetBSD: kern_sleepq.c,v 1.73 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2006, 2007, 2008, 2009, 2019, 2020 The NetBSD Foundation, Inc. @@ -35,7 +35,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.72 2022/06/29 22:10:43 riastradh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.73 2022/06/29 22:27:01 riastradh Exp $"); #include <sys/param.h> #include <sys/kernel.h> @@ -302,14 +302,13 @@ sleepq_uncatch(lwp_t *l) * timo is a timeout in ticks. timo = 0 specifies an infinite timeout. */ int -sleepq_block(int timo, bool catch_p) +sleepq_block(int timo, bool catch_p, struct syncobj *syncobj) { int error = 0, sig; struct proc *p; lwp_t *l = curlwp; bool early = false; int biglocks = l->l_biglocks; - struct syncobj *syncobj = l->l_syncobj; ktrcsw(1, 0, syncobj); diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c index b55f8b20454..48ad3ee1fdd 100644 --- a/sys/kern/kern_synch.c +++ b/sys/kern/kern_synch.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_synch.c,v 1.350 2022/03/10 12:21:25 riastradh Exp $ */ +/* $NetBSD: kern_synch.c,v 1.351 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008, 2009, 2019, 2020 @@ -69,7 +69,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.350 2022/03/10 12:21:25 riastradh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.351 2022/06/29 22:27:01 riastradh Exp $"); #include "opt_kstack.h" #include "opt_dtrace.h" @@ -188,7 +188,7 @@ tsleep(wchan_t ident, pri_t priority, const char *wmesg, int timo) sq = sleeptab_lookup(&sleeptab, ident, &mp); sleepq_enter(sq, l, mp); sleepq_enqueue(sq, ident, wmesg, &sleep_syncobj, catch_p); - return sleepq_block(timo, catch_p); + return sleepq_block(timo, catch_p, &sleep_syncobj); } int @@ -215,7 +215,7 @@ mtsleep(wchan_t ident, pri_t priority, const char *wmesg, int timo, sleepq_enter(sq, l, mp); sleepq_enqueue(sq, ident, wmesg, &sleep_syncobj, catch_p); mutex_exit(mtx); - error = sleepq_block(timo, catch_p); + error = sleepq_block(timo, catch_p, &sleep_syncobj); if ((priority & PNORELOCK) == 0) mutex_enter(mtx); @@ -243,7 +243,7 @@ kpause(const char *wmesg, bool intr, int timo, kmutex_t *mtx) lwp_lock(l); KERNEL_UNLOCK_ALL(NULL, &l->l_biglocks); sleepq_enqueue(NULL, l, wmesg, &kpause_syncobj, intr); - error = sleepq_block(timo, intr); + error = sleepq_block(timo, intr, &kpause_syncobj); if (mtx != NULL) mutex_enter(mtx); diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c index 1f78dabfd6e..3d710613b6f 100644 --- a/sys/kern/kern_timeout.c +++ b/sys/kern/kern_timeout.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_timeout.c,v 1.69 2022/03/30 17:02:02 riastradh Exp $ */ +/* $NetBSD: kern_timeout.c,v 1.70 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2003, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc. @@ -59,7 +59,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.69 2022/03/30 17:02:02 riastradh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.70 2022/06/29 22:27:01 riastradh Exp $"); /* * Timeouts are kept in a hierarchical timing wheel. The c_time is the @@ -543,7 +543,7 @@ callout_wait(callout_impl_t *c, void *interlock, kmutex_t *lock) sleepq_enter(&cc->cc_sleepq, l, cc->cc_lock); sleepq_enqueue(&cc->cc_sleepq, cc, "callout", &sleep_syncobj, false); - sleepq_block(0, false); + sleepq_block(0, false, &sleep_syncobj); } /* diff --git a/sys/kern/kern_turnstile.c b/sys/kern/kern_turnstile.c index 0f9dbdde5ae..26a19fb7ebd 100644 --- a/sys/kern/kern_turnstile.c +++ b/sys/kern/kern_turnstile.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_turnstile.c,v 1.43 2022/05/28 22:08:46 andvar Exp $ */ +/* $NetBSD: kern_turnstile.c,v 1.44 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2002, 2006, 2007, 2009, 2019, 2020 @@ -61,7 +61,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_turnstile.c,v 1.43 2022/05/28 22:08:46 andvar Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_turnstile.c,v 1.44 2022/06/29 22:27:01 riastradh Exp $"); #include <sys/param.h> #include <sys/lockdebug.h> @@ -435,7 +435,7 @@ turnstile_block(turnstile_t *ts, int q, wchan_t obj, syncobj_t *sobj) KPREEMPT_DISABLE(l); KASSERT(lock == l->l_mutex); turnstile_lendpri(l); - sleepq_block(0, false); + sleepq_block(0, false, sobj); l->l_kpribase = obase; KPREEMPT_ENABLE(l); } diff --git a/sys/kern/sys_lwp.c b/sys/kern/sys_lwp.c index e5a2f93ba61..e9e7d2c93a3 100644 --- a/sys/kern/sys_lwp.c +++ b/sys/kern/sys_lwp.c @@ -1,4 +1,4 @@ -/* $NetBSD: sys_lwp.c,v 1.82 2020/05/23 23:42:43 ad Exp $ */ +/* $NetBSD: sys_lwp.c,v 1.83 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2001, 2006, 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc. @@ -35,7 +35,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.82 2020/05/23 23:42:43 ad Exp $"); +__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.83 2022/06/29 22:27:01 riastradh Exp $"); #include <sys/param.h> #include <sys/systm.h> @@ -533,7 +533,7 @@ lwp_park(clockid_t clock_id, int flags, struct timespec *ts) } l->l_biglocks = 0; sleepq_enqueue(NULL, l, "parked", &lwp_park_syncobj, true); - error = sleepq_block(timo, true); + error = sleepq_block(timo, true, &lwp_park_syncobj); switch (error) { case EWOULDBLOCK: error = ETIMEDOUT; diff --git a/sys/kern/sys_select.c b/sys/kern/sys_select.c index e490f304d91..07cc26f15b7 100644 --- a/sys/kern/sys_select.c +++ b/sys/kern/sys_select.c @@ -1,4 +1,4 @@ -/* $NetBSD: sys_select.c,v 1.59 2022/04/09 23:52:05 riastradh Exp $ */ +/* $NetBSD: sys_select.c,v 1.60 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2007, 2008, 2009, 2010, 2019, 2020 The NetBSD Foundation, Inc. @@ -84,7 +84,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: sys_select.c,v 1.59 2022/04/09 23:52:05 riastradh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: sys_select.c,v 1.60 2022/06/29 22:27:01 riastradh Exp $"); #include <sys/param.h> #include <sys/systm.h> @@ -322,7 +322,7 @@ state_check: l->l_kpriority = true; sleepq_enter(&sc->sc_sleepq, l, lock); sleepq_enqueue(&sc->sc_sleepq, sc, opname, &select_sobj, true); - error = sleepq_block(timo, true); + error = sleepq_block(timo, true, &select_sobj); if (error != 0) { break; } diff --git a/sys/sys/sleepq.h b/sys/sys/sleepq.h index c81d99ff652..42b0db2fcea 100644 --- a/sys/sys/sleepq.h +++ b/sys/sys/sleepq.h @@ -1,4 +1,4 @@ -/* $NetBSD: sleepq.h,v 1.34 2020/11/01 20:56:13 christos Exp $ */ +/* $NetBSD: sleepq.h,v 1.35 2022/06/29 22:27:01 riastradh Exp $ */ /*- * Copyright (c) 2002, 2006, 2007, 2008, 2009, 2019, 2020 @@ -60,7 +60,7 @@ void sleepq_wake(sleepq_t *, wchan_t, u_int, kmutex_t *); int sleepq_abort(kmutex_t *, int); void sleepq_changepri(lwp_t *, pri_t); void sleepq_lendpri(lwp_t *, pri_t); -int sleepq_block(int, bool); +int sleepq_block(int, bool, struct syncobj *); #ifdef _KERNEL typedef union { |
