The patch titled jbd: fix race in buffer processing in commit code has been removed from the -mm tree. Its filename was jbd-fix-race-in-buffer-processing-in-commit-code.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: jbd: fix race in buffer processing in commit code From: Jan Kara <jack@xxxxxxx> In commit code, we scan buffers attached to a transaction. During this scan, we sometimes have to drop j_list_lock and then we recheck whether the journal buffer head didn't get freed by journal_try_to_free_buffers(). But checking for buffer_jbd(bh) isn't enough because a new journal head could get attached to our buffer head. So add a check whether the journal head remained the same and whether it's still at the same transaction and list. This is a nasty bug and can cause problems like memory corruption (use after free) or trigger various assertions in JBD code (observed). Signed-off-by: Jan Kara <jack@xxxxxxx> Cc: <stable@xxxxxxxxxx> Cc: <linux-ext4@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/jbd/commit.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff -puN fs/jbd/commit.c~jbd-fix-race-in-buffer-processing-in-commit-code fs/jbd/commit.c --- a/fs/jbd/commit.c~jbd-fix-race-in-buffer-processing-in-commit-code +++ a/fs/jbd/commit.c @@ -241,7 +241,7 @@ write_out_data: spin_lock(&journal->j_list_lock); } /* Someone already cleaned up the buffer? */ - if (!buffer_jbd(bh) + if (!buffer_jbd(bh) || bh2jh(bh) != jh || jh->b_transaction != commit_transaction || jh->b_jlist != BJ_SyncData) { jbd_unlock_bh_state(bh); @@ -478,7 +478,9 @@ void journal_commit_transaction(journal_ spin_lock(&journal->j_list_lock); continue; } - if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) { + if (buffer_jbd(bh) && bh2jh(bh) == jh && + jh->b_transaction == commit_transaction && + jh->b_jlist == BJ_Locked) { __journal_unfile_buffer(jh); jbd_unlock_bh_state(bh); journal_remove_journal_head(bh); _ Patches currently in -mm which might be from jack@xxxxxxx are linux-next.patch jbd2-clean-up-jbd2_journal_try_to_free_buffers.patch vfs-split-generic_forget_inode-so-that-hugetlbfs-does-not-have-to-copy-it.patch mm-remove-__invalidate_mapping_pages-variant.patch writeback-skip-new-or-to-be-freed-inodes.patch ext2-do-not-update-mtime-of-a-moved-directory.patch ext3-fix-chain-verification-in-ext3_get_blocks.patch jbd-clean-up-journal_try_to_free_buffers.patch ext3-make-sure-inode-is-deleted-from-orphan-list-after-truncate.patch isofs-let-mode-and-dmode-mount-options-override-rock-ridge-mode-setting.patch isofs-fix-setting-of-uid-and-gid-to-0.patch isofs-cleanup-mount-option-processing.patch reiser4-update-names-of-quota-methods.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html