On 08/19/2010 12:59 PM, Eric Sandeen wrote: > Our QA reported an oops in the ext4_mb_release_group_pa tracing, > and Josef Bacik pointed out that it was because we may have a > non-null but uninitialized ac_inode in the allocation context. > > I can reproduce it when running xfstests with ext4 tracepoints on, > on a CONFIG_SLAB_DEBUG kernel. > > We call trace_ext4_mb_release_group_pa from 2 places, > ext4_mb_discard_group_preallocations and > ext4_mb_discard_lg_preallocations > > In both cases we allocate an ac as a container just for tracing (!) > and never fill in the ac_inode. There's no reason to be assigning, > testing, or printing it as far as I can see, so just remove it from > the tracepoint. Ping on this one at least? avoid-null-dereference-in-trace_ext4_mballoc_discard is in the patch queue, this one is similar and should go with it. I'd really like to see [PATCH] don't use ext4_allocation_contexts for tracing go soon as well so we stop abusing the slab cache all day long... Thanks, -Eric > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > --- > > diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h > index 01e9e00..e352c77 100644 > --- a/include/trace/events/ext4.h > +++ b/include/trace/events/ext4.h > @@ -432,7 +432,6 @@ TRACE_EVENT(ext4_mb_release_group_pa, > > TP_STRUCT__entry( > __field( dev_t, dev ) > - __field( ino_t, ino ) > __field( __u64, pa_pstart ) > __field( __u32, pa_len ) > > @@ -440,8 +439,6 @@ TRACE_EVENT(ext4_mb_release_group_pa, > > TP_fast_assign( > __entry->dev = sb->s_dev; > - __entry->ino = (ac && ac->ac_inode) ? > - ac->ac_inode->i_ino : 0; > __entry->pa_pstart = pa->pa_pstart; > __entry->pa_len = pa->pa_len; > ), > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
