The patch titled sys_swapon: fix inode locking has been removed from the -mm tree. Its filename was sys_swapon-fix-inode-locking.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: sys_swapon: fix inode locking From: Cesar Eduardo Barros <cesarb@xxxxxxxxxx> A conflict between 52c50567d8ab0a0a87f12cceaa4194967854f0bd (mm: swap: unlock swapfile inode mutex before closing file on bad swapfiles) and 83ef99befc324803a54cf2a5fab5a322df3a99d6 (sys_swapon: remove did_down variable) caused a double unlock of the inode mutex (once in bad_swap: before the filp_close, once at the end just before returning). The patch which added the extra unlock cleared did_down to avoid unlocking twice, but the other patch removed the did_down variable. To fix, set inode to NULL after the first unlock, since it will be used after that point only for the final unlock. While checking this patch, I found a path which could unlock without locking, in case the same inode was added as a swapfile twice. To fix, move the setting of the inode variable further down, to just before claim_swapfile, which will lock the inode before doing anything else. Signed-off-by: Cesar Eduardo Barros <cesarb@xxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Eric B Munson <emunson@xxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff -puN mm/swapfile.c~sys_swapon-fix-inode-locking mm/swapfile.c --- a/mm/swapfile.c~sys_swapon-fix-inode-locking +++ a/mm/swapfile.c @@ -2088,7 +2088,6 @@ SYSCALL_DEFINE2(swapon, const char __use p->swap_file = swap_file; mapping = swap_file->f_mapping; - inode = mapping->host; for (i = 0; i < nr_swapfiles; i++) { struct swap_info_struct *q = swap_info[i]; @@ -2101,6 +2100,8 @@ SYSCALL_DEFINE2(swapon, const char __use } } + inode = mapping->host; + /* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */ error = claim_swapfile(p, inode); if (unlikely(error)) goto bad_swap; @@ -2187,8 +2188,10 @@ bad_swap: spin_unlock(&swap_lock); vfree(swap_map); if (swap_file) { - if (inode && S_ISREG(inode->i_mode)) + if (inode && S_ISREG(inode->i_mode)) { mutex_unlock(&inode->i_mutex); + inode = NULL; + } filp_close(swap_file, NULL); } out: _ Patches currently in -mm which might be from cesarb@xxxxxxxxxx are origin.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