| Message ID | 1324704531.2915.43.camel@edumazet-laptop |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Sat, 24 Dec 2011 06:28:51 +0100 Eric Dumazet <eric.dumazet@gmail.com> wrote: > commit 6373a9a286 (netem: use vmalloc for distribution table) added a > regression, since vfree() is called while holding a spinlock and BH > being disabled. > > Fix this by doing the pointers swap in critical section, and freeing > after spinlock release. > > Also add __GFP_NOWARN to the kmalloc() try, since we fallback to > vmalloc(). > > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > --- > net/sched/sch_netem.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c > index eb3b9a8..a4ab207 100644 > --- a/net/sched/sch_netem.c > +++ b/net/sched/sch_netem.c > @@ -488,7 +488,7 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) > return -EINVAL; > > s = sizeof(struct disttable) + n * sizeof(s16); > - d = kmalloc(s, GFP_KERNEL); > + d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); > if (!d) > d = vmalloc(s); > if (!d) > @@ -501,9 +501,10 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) > root_lock = qdisc_root_sleeping_lock(sch); > > spin_lock_bh(root_lock); > - dist_free(q->delay_dist); > - q->delay_dist = d; > + swap(q->delay_dist, d); > spin_unlock_bh(root_lock); > + > + dist_free(d); > return 0; > } Acked-by: Stephen Hemminger <shemminger@vyatta.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Stephen Hemminger <shemminger@vyatta.com> Date: Sat, 24 Dec 2011 11:18:54 -0800 > On Sat, 24 Dec 2011 06:28:51 +0100 > Eric Dumazet <eric.dumazet@gmail.com> wrote: > >> commit 6373a9a286 (netem: use vmalloc for distribution table) added a >> regression, since vfree() is called while holding a spinlock and BH >> being disabled. >> >> Fix this by doing the pointers swap in critical section, and freeing >> after spinlock release. >> >> Also add __GFP_NOWARN to the kmalloc() try, since we fallback to >> vmalloc(). >> >> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> ... > Acked-by: Stephen Hemminger <shemminger@vyatta.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index eb3b9a8..a4ab207 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -488,7 +488,7 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) return -EINVAL; s = sizeof(struct disttable) + n * sizeof(s16); - d = kmalloc(s, GFP_KERNEL); + d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); if (!d) d = vmalloc(s); if (!d) @@ -501,9 +501,10 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) root_lock = qdisc_root_sleeping_lock(sch); spin_lock_bh(root_lock); - dist_free(q->delay_dist); - q->delay_dist = d; + swap(q->delay_dist, d); spin_unlock_bh(root_lock); + + dist_free(d); return 0; }
commit 6373a9a286 (netem: use vmalloc for distribution table) added a regression, since vfree() is called while holding a spinlock and BH being disabled. Fix this by doing the pointers swap in critical section, and freeing after spinlock release. Also add __GFP_NOWARN to the kmalloc() try, since we fallback to vmalloc(). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> --- net/sched/sch_netem.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html