Zhiqiang Liu be23e83733 bcache: fix potential deadlock problem in btree_gc_coalesce ... coccicheck reports: drivers/md//bcache/btree.c:1538:1-7: preceding lock on line 1417 In btree_gc_coalesce func, if the coalescing process fails, we will goto to out_nocoalesce tag directly without releasing new_nodes[i]->write_lock. Then, it will cause a deadlock when trying to acquire new_nodes[i]-> write_lock for freeing new_nodes[i] before return. btree_gc_coalesce func details as follows: if alloc new_nodes[i] fails: goto out_nocoalesce; // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock) // main coalescing process for (i = nodes - 1; i > 0; --i) [snipped] if coalescing process fails: // Here, directly goto out_nocoalesce // tag will cause a deadlock goto out_nocoalesce; [snipped] // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock) // coalesing succ, return return; out_nocoalesce: btree_node_free(new_nodes[i]) // free new_nodes[i] // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock); // set flag for reuse clear_bit(BTREE_NODE_dirty, &ew_nodes[i]->flags); // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock); To fix the problem, we add a new tag 'out_unlock_nocoalesce' for releasing new_nodes[i]->write_lock before out_nocoalesce tag. If coalescing process fails, we will go to out_unlock_nocoalesce tag for releasing new_nodes[i]->write_lock before free new_nodes[i] in out_nocoalesce tag. (Coly Li helps to clean up commit log format.) Fixes: 2a285686c1 ("bcache: btree locking rework") Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2020-06-14 16:47:56 -06:00
..
alloc.c	Revert "bcache: ignore pending signals when creating gc and allocator thread"	2020-03-02 20:01:32 -07:00
bcache.h	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
bset.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
bset.h	bcache: explicity type cast in bset_bkey_last()	2020-02-01 07:55:39 -07:00
btree.c	bcache: fix potential deadlock problem in btree_gc_coalesce	2020-06-14 16:47:56 -06:00
btree.h	bcache: remove dupplicated declaration from btree.h	2020-03-24 19:56:42 -06:00
closure.c
closure.h
debug.c
debug.h
extents.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
extents.h
io.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
journal.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
journal.h
Kconfig	bcache: configure the asynchronous registertion to be experimental	2020-05-27 05:19:36 -06:00
Makefile
movinggc.c
request.c	for-5.8/drivers-2020-06-01	2020-06-02 15:37:03 -07:00
request.h	bcache: pass the make_request methods to blk_queue_make_request	2020-03-27 10:23:43 -06:00
stats.c	bcache: fix memory corruption in bch_cache_accounting_clear()	2020-02-01 07:55:39 -07:00
stats.h
super.c	bcache: configure the asynchronous registertion to be experimental	2020-05-27 05:19:36 -06:00
sysfs.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
sysfs.h
trace.c
util.c
util.h
writeback.c	bcache: Convert pr_<level> uses to a more typical style	2020-05-27 05:19:36 -06:00
writeback.h	bcache: make bch_sectors_dirty_init() to be multithreaded	2020-03-22 10:06:57 -06:00