Re: [PATCH] nbd: hold tags->lock to prevent access freed request through blk_mq_tag_to_rq()
From: yukuai (C)
Date: Sat Aug 07 2021 - 22:42:46 EST
On 2021/08/07 2:05, kernel test robot wrote:
Hi Yu,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on block/for-next]
[also build test ERROR on v5.14-rc4 next-20210805]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Yu-Kuai/nbd-hold-tags-lock-to-prevent-access-freed-request-through-blk_mq_tag_to_rq/20210806-173619
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: ia64-randconfig-r025-20210804 (attached as .config)
compiler: ia64-linux-gcc (GCC) 10.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/8fe3c93026bf70921973f34fd9dc2bcf4ca2ccf0
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Yu-Kuai/nbd-hold-tags-lock-to-prevent-access-freed-request-through-blk_mq_tag_to_rq/20210806-173619
git checkout 8fe3c93026bf70921973f34fd9dc2bcf4ca2ccf0
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All errors (new ones prefixed by >>):
In file included from include/linux/wait.h:9,
from include/linux/pid.h:6,
from include/linux/sched.h:14,
from include/linux/blkdev.h:5,
from drivers/block/nbd.c:16:
drivers/block/nbd.c: In function 'nbd_read_stat':
drivers/block/nbd.c:719:26: error: invalid use of undefined type 'struct blk_mq_tags'
719 | spin_lock_irqsave(&tags->lock, flags);
| ^~
My apologize that I forgot to enable nbd conifg while compiling this
patch in my local enviroment.
Thanks
Kuai
include/linux/spinlock.h:252:34: note: in definition of macro 'raw_spin_lock_irqsave'
252 | flags = _raw_spin_lock_irqsave(lock); \
| ^~~~
drivers/block/nbd.c:719:3: note: in expansion of macro 'spin_lock_irqsave'
719 | spin_lock_irqsave(&tags->lock, flags);
| ^~~~~~~~~~~~~~~~~
drivers/block/nbd.c:726:31: error: invalid use of undefined type 'struct blk_mq_tags'
726 | spin_unlock_irqrestore(&tags->lock, flags);
| ^~
vim +719 drivers/block/nbd.c
680
681 /* NULL returned = something went wrong, inform userspace */
682 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
683 {
684 struct nbd_config *config = nbd->config;
685 int result;
686 struct nbd_reply reply;
687 struct nbd_cmd *cmd;
688 struct request *req = NULL;
689 u64 handle;
690 u16 hwq;
691 u32 tag;
692 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
693 struct iov_iter to;
694 int ret = 0;
695
696 reply.magic = 0;
697 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
698 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
699 if (result <= 0) {
700 if (!nbd_disconnected(config))
701 dev_err(disk_to_dev(nbd->disk),
702 "Receive control failed (result %d)\n", result);
703 return ERR_PTR(result);
704 }
705
706 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
707 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
708 (unsigned long)ntohl(reply.magic));
709 return ERR_PTR(-EPROTO);
710 }
711
712 memcpy(&handle, reply.handle, sizeof(handle));
713 tag = nbd_handle_to_tag(handle);
714 hwq = blk_mq_unique_tag_to_hwq(tag);
715 if (hwq < nbd->tag_set.nr_hw_queues) {
716 unsigned long flags;
717 struct blk_mq_tags *tags = nbd->tag_set.tags[hwq];
718
> 719 spin_lock_irqsave(&tags->lock, flags);
720 req = blk_mq_tag_to_rq(tags, blk_mq_unique_tag_to_tag(tag));
721 if (!blk_mq_request_started(req)) {
722 dev_err(disk_to_dev(nbd->disk), "Request not started (%d) %p\n",
723 tag, req);
724 req = NULL;
725 }
726 spin_unlock_irqrestore(&tags->lock, flags);
727 }
728
729 if (!req) {
730 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d)\n", tag);
731 return ERR_PTR(-ENOENT);
732 }
733 trace_nbd_header_received(req, handle);
734 cmd = blk_mq_rq_to_pdu(req);
735
736 mutex_lock(&cmd->lock);
737 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
738 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
739 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
740 ret = -ENOENT;
741 goto out;
742 }
743 if (cmd->status != BLK_STS_OK) {
744 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
745 req);
746 ret = -ENOENT;
747 goto out;
748 }
749 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
750 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
751 req);
752 ret = -ENOENT;
753 goto out;
754 }
755 if (ntohl(reply.error)) {
756 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
757 ntohl(reply.error));
758 cmd->status = BLK_STS_IOERR;
759 goto out;
760 }
761
762 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
763 if (rq_data_dir(req) != WRITE) {
764 struct req_iterator iter;
765 struct bio_vec bvec;
766
767 rq_for_each_segment(bvec, req, iter) {
768 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
769 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
770 if (result <= 0) {
771 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
772 result);
773 /*
774 * If we've disconnected, we need to make sure we
775 * complete this request, otherwise error out
776 * and let the timeout stuff handle resubmitting
777 * this request onto another connection.
778 */
779 if (nbd_disconnected(config)) {
780 cmd->status = BLK_STS_IOERR;
781 goto out;
782 }
783 ret = -EIO;
784 goto out;
785 }
786 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
787 req, bvec.bv_len);
788 }
789 }
790 out:
791 trace_nbd_payload_received(req, handle);
792 mutex_unlock(&cmd->lock);
793 return ret ? ERR_PTR(ret) : cmd;
794 }
795
---
0-DAY CI Kernel Test Service, Intel Corporation
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