e11e511617
write-zeros has a bio, but does not have any data buffers associated with it. Hence should not initialize the request iter for it (which attempts to reference the bi_io_vec (and crash). -- run blktests nvme/012 at 2021-02-05 21:53:34 BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 15 PID: 12069 Comm: kworker/15:2H Tainted: G S I 5.11.0-rc6+ #1 Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.10.0 11/12/2020 Workqueue: kblockd blk_mq_run_work_fn RIP: 0010:nvme_tcp_init_iter+0x7d/0xd0 [nvme_tcp] RSP: 0018:ffffbd084447bd18 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffa0bba9f3ce80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000002000000 RBP: ffffa0ba8ac6fec0 R08: 0000000002000000 R09: 0000000000000000 R10: 0000000002800809 R11: 0000000000000000 R12: 0000000000000000 R13: ffffa0bba9f3cf90 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffffa0c9ff9c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 00000001c9c6c005 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: nvme_tcp_queue_rq+0xef/0x330 [nvme_tcp] blk_mq_dispatch_rq_list+0x11c/0x7c0 ? blk_mq_flush_busy_ctxs+0xf6/0x110 __blk_mq_sched_dispatch_requests+0x12b/0x170 blk_mq_sched_dispatch_requests+0x30/0x60 __blk_mq_run_hw_queue+0x2b/0x60 process_one_work+0x1cb/0x360 ? process_one_work+0x360/0x360 worker_thread+0x30/0x370 ? process_one_work+0x360/0x360 kthread+0x116/0x130 ? kthread_park+0x80/0x80 ret_from_fork+0x1f/0x30 -- Fixes: cb9b870fba3e ("nvme-tcp: fix wrong setting of request iov_iter") Reported-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.