On Mon, 23 Oct 2023 17:23:28 GMT Mateusz Guzik <[email protected]> wrote:
> The branch main has been updated by mjg: > > URL: > https://cgit.FreeBSD.org/src/commit/?id=c35f527ed115b792463d30c7d3c8904e435caead > > commit c35f527ed115b792463d30c7d3c8904e435caead > Author: Mateusz Guzik <[email protected]> > AuthorDate: 2023-10-23 17:22:12 +0000 > Commit: Mateusz Guzik <[email protected]> > CommitDate: 2023-10-23 17:22:12 +0000 > > sx: unset td_wantedlock around going to sleep > > Otherwise it can crash in sleepq_wait_sig -> sleepq_catch_signals -> > sig_ast_checksusp -> thread_suspend_check due to a mutex acquire. > > Reported by: pho > Sponsored by: Rubicon Communications, LLC ("Netgate") > --- > sys/kern/kern_sx.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c > index bc8a1214689f..455ae165e328 100644 > --- a/sys/kern/kern_sx.c > +++ b/sys/kern/kern_sx.c > @@ -854,10 +854,17 @@ retry_sleepq: > sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, > SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? > SLEEPQ_INTERRUPTIBLE : 0), SQ_EXCLUSIVE_QUEUE); > + /* > + * Hack: this can land in thread_suspend_check which will > + * conditionally take a mutex, tripping over an assert if a > + * lock we are waiting for is set. > + */ > + THREAD_CONTENTION_DONE(&sx->lock_object); > if (!(opts & SX_INTERRUPTIBLE)) > sleepq_wait(&sx->lock_object, 0); > else > error = sleepq_wait_sig(&sx->lock_object, 0); > + THREAD_CONTENTION_DONE(&sx->lock_object); should this be THREAD_CONTENDS_ON_LOCK, like below? > #ifdef KDTRACE_HOOKS > sleep_time += lockstat_nsecs(&sx->lock_object); > sleep_cnt++; > @@ -1209,10 +1216,17 @@ retry_sleepq: > sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, > SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? > SLEEPQ_INTERRUPTIBLE : 0), SQ_SHARED_QUEUE); > + /* > + * Hack: this can land in thread_suspend_check which will > + * conditionally take a mutex, tripping over an assert if a > + * lock we are waiting for is set. > + */ > + THREAD_CONTENTION_DONE(&sx->lock_object); > if (!(opts & SX_INTERRUPTIBLE)) > sleepq_wait(&sx->lock_object, 0); > else > error = sleepq_wait_sig(&sx->lock_object, 0); > + THREAD_CONTENDS_ON_LOCK(&sx->lock_object); > #ifdef KDTRACE_HOOKS > sleep_time += lockstat_nsecs(&sx->lock_object); > sleep_cnt++; > -- Gary Jennejohn
