A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-30 03:27:44 -04:00
Code Issues Projects Releases Packages Wiki Activity

fs: fix superblock iteration race

Browse source 
list_for_each_entry_safe is not suitable to protect against concurrent
modification of the list. 6754af6 introduced a race in sb walking.

list_for_each_entry can use the trick of pinning the current entry in
the list before we drop and retake the lock because it subsequently
follows cur->next. However list_for_each_entry_safe saves n=cur->next
for following before entering the loop body, so when the lock is
dropped, n may be deleted.

Signed-off-by: Nick Piggin <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Frank Mayhar <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
[email protected] 2010-06-24 13:02:14 +10:00 • committed by Linus Torvalds
commit 57439f878a
3 changed files with 23 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

6
fs/super.c
View file

@ -374,6 +374,8 @@ void sync_supers(void)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
/* lock was dropped, must reset next */
list_safe_reset_next(sb, n, s_list);
__put_super(sb);
}
}
@ -405,6 +407,8 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
/* lock was dropped, must reset next */
list_safe_reset_next(sb, n, s_list);
__put_super(sb);
}
spin_unlock(&sb_lock);
@ -585,6 +589,8 @@ static void do_emergency_remount(struct work_struct *work)
}
up_write(&sb->s_umount);
spin_lock(&sb_lock);
/* lock was dropped, must reset next */
list_safe_reset_next(sb, n, s_list);
__put_super(sb);
}
spin_unlock(&sb_lock);