-stable review patch. If anyone has any objections, please let us know. --------------------- From: Wu Fengguang upstream commit: b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so _outside_ of inode_lock. So any I_FREEING testing is incomplete without a coupled testing of I_CLEAR. So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and add_dquot_ref(). Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara reminds fixing the other two cases. Masayoshi MIZUMA has a nice panic flow: ===================================================================== [process A] | [process B] | | | prune_icache() | drop_pagecache() | spin_lock(&inode_lock) | drop_pagecache_sb() | inode->i_state |= I_FREEING; | | | spin_unlock(&inode_lock) | V | | | spin_lock(&inode_lock) | V | | | dispose_list() | | | list_del() | | | clear_inode() | | | inode->i_state = I_CLEAR | | | | | V | | | if (inode->i_state & (I_FREEING|I_WILL_FREE)) | | | continue; <==== NOT MATCH | | | | | | (DANGER from here on! Accessing disposing inode!) | | | | | | __iget() | | | list_move() <===== PANIC on poisoned list !! V V | (time) ===================================================================== Reported-by: Masayoshi MIZUMA Reviewed-by: Jan Kara Signed-off-by: Wu Fengguang Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [chrisw: backport to 2.6.29] Signed-off-by: Chris Wright --- fs/dquot.c | 2 +- fs/drop_caches.c | 2 +- fs/fs-writeback.c | 3 ++- 3 files changed, 4 insertions(+), 3 deletions(-) --- a/fs/drop_caches.c +++ b/fs/drop_caches.c @@ -18,7 +18,7 @@ static void drop_pagecache_sb(struct sup spin_lock(&inode_lock); list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { - if (inode->i_state & (I_FREEING|I_WILL_FREE)) + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) continue; if (inode->i_mapping->nrpages == 0) continue; --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -538,7 +538,8 @@ void generic_sync_sb_inodes(struct super list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { struct address_space *mapping; - if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) + if (inode->i_state & + (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) continue; mapping = inode->i_mapping; if (mapping->nrpages == 0) --- a/fs/dquot.c +++ b/fs/dquot.c @@ -793,7 +793,7 @@ static void add_dquot_ref(struct super_b continue; if (!dqinit_needed(inode, type)) continue; - if (inode->i_state & (I_FREEING|I_WILL_FREE)) + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) continue; __iget(inode); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/