From e5880d76aea443b04e07da19830da0f6f7494eef Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Tue, 27 Jul 2010 11:56:04 -0400 Subject: [PATCH] ext4: fix potential NULL dereference while tracing The allocation_context pointer can be NULL. Signed-off-by: "Theodore Ts'o" --- fs/ext4/mballoc.c | 4 ++-- include/trace/events/ext4.h | 20 ++++++++++++-------- 2 files changed, 14 insertions(+), 10 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 3dfad95f0f9..8b3b9344a59 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3575,7 +3575,7 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh, trace_ext4_mballoc_discard(ac); } - trace_ext4_mb_release_inode_pa(ac, pa, grp_blk_start + bit, + trace_ext4_mb_release_inode_pa(sb, ac, pa, grp_blk_start + bit, next - bit); mb_free_blocks(pa->pa_inode, e4b, bit, next - bit); bit = next + 1; @@ -3606,7 +3606,7 @@ ext4_mb_release_group_pa(struct ext4_buddy *e4b, ext4_group_t group; ext4_grpblk_t bit; - trace_ext4_mb_release_group_pa(ac, pa); + trace_ext4_mb_release_group_pa(sb, ac, pa); BUG_ON(pa->pa_deleted == 0); ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); BUG_ON(group != e4b->bd_group && pa->pa_len != 0); diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h index f3865c7b416..01e9e0076a9 100644 --- a/include/trace/events/ext4.h +++ b/include/trace/events/ext4.h @@ -395,11 +395,12 @@ DEFINE_EVENT(ext4__mb_new_pa, ext4_mb_new_group_pa, ); TRACE_EVENT(ext4_mb_release_inode_pa, - TP_PROTO(struct ext4_allocation_context *ac, + TP_PROTO(struct super_block *sb, + struct ext4_allocation_context *ac, struct ext4_prealloc_space *pa, unsigned long long block, unsigned int count), - TP_ARGS(ac, pa, block, count), + TP_ARGS(sb, ac, pa, block, count), TP_STRUCT__entry( __field( dev_t, dev ) @@ -410,8 +411,9 @@ TRACE_EVENT(ext4_mb_release_inode_pa, ), TP_fast_assign( - __entry->dev = ac->ac_sb->s_dev; - __entry->ino = ac->ac_inode->i_ino; + __entry->dev = sb->s_dev; + __entry->ino = (ac && ac->ac_inode) ? + ac->ac_inode->i_ino : 0; __entry->block = block; __entry->count = count; ), @@ -422,10 +424,11 @@ TRACE_EVENT(ext4_mb_release_inode_pa, ); TRACE_EVENT(ext4_mb_release_group_pa, - TP_PROTO(struct ext4_allocation_context *ac, + TP_PROTO(struct super_block *sb, + struct ext4_allocation_context *ac, struct ext4_prealloc_space *pa), - TP_ARGS(ac, pa), + TP_ARGS(sb, ac, pa), TP_STRUCT__entry( __field( dev_t, dev ) @@ -436,8 +439,9 @@ TRACE_EVENT(ext4_mb_release_group_pa, ), TP_fast_assign( - __entry->dev = ac->ac_sb->s_dev; - __entry->ino = ac->ac_inode->i_ino; + __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; ), -- 2.11.4.GIT