4.19-stable review patch. If anyone has any objections, please let me know.
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From: Markus Weippert markus@gekmihesg.de
commit bb6cc253861bd5a7cf8439e2118659696df9619f upstream.
Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") replaced IS_ERR_OR_NULL by IS_ERR. This leads to a NULL pointer dereference.
BUG: kernel NULL pointer dereference, address: 0000000000000080 Call Trace: ? __die_body.cold+0x1a/0x1f ? page_fault_oops+0xd2/0x2b0 ? exc_page_fault+0x70/0x170 ? asm_exc_page_fault+0x22/0x30 ? btree_node_free+0xf/0x160 [bcache] ? up_write+0x32/0x60 btree_gc_coalesce+0x2aa/0x890 [bcache] ? bch_extent_bad+0x70/0x170 [bcache] btree_gc_recurse+0x130/0x390 [bcache] ? btree_gc_mark_node+0x72/0x230 [bcache] bch_btree_gc+0x5da/0x600 [bcache] ? cpuusage_read+0x10/0x10 ? bch_btree_gc+0x600/0x600 [bcache] bch_gc_thread+0x135/0x180 [bcache]
The relevant code starts with:
new_nodes[0] = NULL;
for (i = 0; i < nodes; i++) { if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key))) goto out_nocoalesce; // ... out_nocoalesce: // ... for (i = 0; i < nodes; i++) if (!IS_ERR(new_nodes[i])) { // IS_ERR_OR_NULL before 028ddcac477b btree_node_free(new_nodes[i]); // new_nodes[0] is NULL rw_unlock(true, new_nodes[i]); }
This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this.
Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") Link: https://lore.kernel.org/all/3DF4A87A-2AC1-4893-AE5F-E921478419A9@suse.de/ Cc: stable@vger.kernel.org Cc: Zheng Wang zyytlz.wz@163.com Cc: Coly Li colyli@suse.de Signed-off-by: Markus Weippert markus@gekmihesg.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/bcache/btree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1526,7 +1526,7 @@ out_nocoalesce: atomic_dec(&b->c->prio_blocked);
for (i = 0; i < nodes; i++) - if (!IS_ERR(new_nodes[i])) { + if (!IS_ERR_OR_NULL(new_nodes[i])) { btree_node_free(new_nodes[i]); rw_unlock(true, new_nodes[i]); }