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Commit e5880d76 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: fix potential NULL dereference while tracing 



The allocation_context pointer can be NULL.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 89eeddf0

fs/ext4/mballoc.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

include/trace/events/ext4.h

+12 −8
Original line number Diff line number Diff line
@@ -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;

	),