This patch addresses an irq free warning and null pointer dereference
error problem when nvme devices got timeout error during initialization.
This problem happens when nvme_timeout() function is called while
nvme_reset_work() is still in execution. This patch fixed the problem by
setting flag of the problematic request to NVME_REQ_CANCELLED before
calling nvme_dev_disable() to make sure __nvme_submit_sync_cmd() returns
an error code and let nvme_submit_sync_cmd() fail gracefully.
The following is console output.

[   62.472097] nvme nvme0: I/O 13 QID 0 timeout, disable controller
[   62.488796] nvme nvme0: could not set timestamp (881)
[   62.494888] ------------[ cut here ]------------
[   62.495142] Trying to free already-free IRQ 11
[   62.495366] WARNING: CPU: 0 PID: 7 at kernel/irq/manage.c:1751 free_irq+0x1f7/0x370
[   62.495742] Modules linked in:
[   62.495902] CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.8.0+ #8
[   62.496206] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-p4
[   62.496772] Workqueue: nvme-reset-wq nvme_reset_work
[   62.497019] RIP: 0010:free_irq+0x1f7/0x370
[   62.497223] Code: e8 ce 49 11 00 48 83 c4 08 4c 89 e0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 44 89 f6 48 c70
[   62.498133] RSP: 0000:ffffa96800043d40 EFLAGS: 00010086
[   62.498391] RAX: 0000000000000000 RBX: ffff9b87fc458400 RCX: 0000000000000000
[   62.498741] RDX: 0000000000000001 RSI: 0000000000000096 RDI: ffffffff9693d72c
[   62.499091] RBP: ffff9b87fd4c8f60 R08: ffffa96800043bfd R09: 0000000000000163
[   62.499440] R10: ffffa96800043bf8 R11: ffffa96800043bfd R12: ffff9b87fd4c8e00
[   62.499790] R13: ffff9b87fd4c8ea4 R14: 000000000000000b R15: ffff9b87fd76b000
[   62.500140] FS:  0000000000000000(0000) GS:ffff9b87fdc00000(0000) knlGS:0000000000000000
[   62.500534] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   62.500816] CR2: 0000000000000000 CR3: 000000003aa0a000 CR4: 00000000000006f0
[   62.501165] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   62.501515] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   62.501864] Call Trace:
[   62.501993]  pci_free_irq+0x13/0x20
[   62.502167]  nvme_reset_work+0x5d0/0x12a0
[   62.502369]  ? update_load_avg+0x59/0x580
[   62.502569]  ? ttwu_queue_wakelist+0xa8/0xc0
[   62.502780]  ? try_to_wake_up+0x1a2/0x450
[   62.502979]  process_one_work+0x1d2/0x390
[   62.503179]  worker_thread+0x45/0x3b0
[   62.503361]  ? process_one_work+0x390/0x390
[   62.503568]  kthread+0xf9/0x130
[   62.503726]  ? kthread_park+0x80/0x80
[   62.503911]  ret_from_fork+0x22/0x30
[   62.504090] ---[ end trace de9ed4a70f8d71e2 ]---
[  123.912275] nvme nvme0: I/O 12 QID 0 timeout, disable controller
[  123.914670] nvme nvme0: 1/0/0 default/read/poll queues
[  123.916310] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  123.917469] #PF: supervisor write access in kernel mode
[  123.917725] #PF: error_code(0x0002) - not-present page
[  123.917976] PGD 0 P4D 0
[  123.918109] Oops: 0002 [#1] SMP PTI
[  123.918283] CPU: 0 PID: 7 Comm: kworker/u4:0 Tainted: G        W         5.8.0+ #8
[  123.918650] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-p4
[  123.919219] Workqueue: nvme-reset-wq nvme_reset_work
[  123.919469] RIP: 0010:__blk_mq_alloc_map_and_request+0x21/0x80
[  123.919757] Code: 66 0f 1f 84 00 00 00 00 00 41 55 41 54 55 48 63 ee 53 48 8b 47 68 89 ee 48 89 fb 8b4
[  123.920657] RSP: 0000:ffffa96800043d40 EFLAGS: 00010286
[  123.920912] RAX: ffff9b87fc4fee40 RBX: ffff9b87fc8cb008 RCX: 0000000000000000
[  123.921258] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9b87fc618000
[  123.921602] RBP: 0000000000000000 R08: ffff9b87fdc2c4a0 R09: ffff9b87fc616000
[  123.921949] R10: 0000000000000000 R11: ffff9b87fffd1500 R12: 0000000000000000
[  123.922295] R13: 0000000000000000 R14: ffff9b87fc8cb200 R15: ffff9b87fc8cb000
[  123.922641] FS:  0000000000000000(0000) GS:ffff9b87fdc00000(0000) knlGS:0000000000000000
[  123.923032] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  123.923312] CR2: 0000000000000000 CR3: 000000003aa0a000 CR4: 00000000000006f0
[  123.923660] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  123.924007] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  123.924353] Call Trace:
[  123.924479]  blk_mq_alloc_tag_set+0x137/0x2a0
[  123.924694]  nvme_reset_work+0xed6/0x12a0
[  123.924898]  process_one_work+0x1d2/0x390
[  123.925099]  worker_thread+0x45/0x3b0
[  123.925280]  ? process_one_work+0x390/0x390
[  123.925486]  kthread+0xf9/0x130
[  123.925642]  ? kthread_park+0x80/0x80
[  123.925825]  ret_from_fork+0x22/0x30
[  123.926004] Modules linked in:
[  123.926158] CR2: 0000000000000000
[  123.926322] ---[ end trace de9ed4a70f8d71e3 ]---
[  123.926549] RIP: 0010:__blk_mq_alloc_map_and_request+0x21/0x80
[  123.926832] Code: 66 0f 1f 84 00 00 00 00 00 41 55 41 54 55 48 63 ee 53 48 8b 47 68 89 ee 48 89 fb 8b4
[  123.927734] RSP: 0000:ffffa96800043d40 EFLAGS: 00010286
[  123.927989] RAX: ffff9b87fc4fee40 RBX: ffff9b87fc8cb008 RCX: 0000000000000000
[  123.928336] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9b87fc618000
[  123.928679] RBP: 0000000000000000 R08: ffff9b87fdc2c4a0 R09: ffff9b87fc616000
[  123.929025] R10: 0000000000000000 R11: ffff9b87fffd1500 R12: 0000000000000000
[  123.929370] R13: 0000000000000000 R14: ffff9b87fc8cb200 R15: ffff9b87fc8cb000
[  123.929715] FS:  0000000000000000(0000) GS:ffff9b87fdc00000(0000) knlGS:0000000000000000
[  123.930106] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  123.930384] CR2: 0000000000000000 CR3: 000000003aa0a000 CR4: 00000000000006f0
[  123.930731] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  123.931077] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Co-developed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>