Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

nvme: fix multipath crash caused by flush request when blktrace is enabled

The flush request initialized by blk_kick_flush has NULL bio, and it may be dealt with nvme_end_req during io completion. When blktrace is enabled, nvme_trace_bio_complete with multipath activated trying to access NULL pointer bio from flush request results in the following crash:

[ 2517.831677] BUG: kernel NULL pointer dereference, address: 000000000000001a [ 2517.835213] #PF: supervisor read access in kernel mode [ 2517.838724] #PF: error_code(0x0000) - not-present page [ 2517.842222] PGD 7b2d51067 P4D 0 [ 2517.845684] Oops: 0000 [#1] SMP NOPTI [ 2517.849125] CPU: 2 PID: 732 Comm: kworker/2:1H Kdump: loaded Tainted: G S 5.15.67-0.cl9.x86_64 #1 [ 2517.852723] Hardware name: XFUSION 2288H V6/BC13MBSBC, BIOS 1.13 07/27/2022 [ 2517.856358] Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp] [ 2517.859993] RIP: 0010:blk_add_trace_bio_complete+0x6/0x30 [ 2517.863628] Code: 1f 44 00 00 48 8b 46 08 31 c9 ba 04 00 10 00 48 8b 80 50 03 00 00 48 8b 78 50 e9 e5 fe ff ff 0f 1f 44 00 00 41 54 49 89 f4 55 <0f> b6 7a 1a 48 89 d5 e8 3e 1c 2b 00 48 89 ee 4c 89 e7 5d 89 c1 ba [ 2517.871269] RSP: 0018:ff7f6a008d9dbcd0 EFLAGS: 00010286 [ 2517.875081] RAX: ff3d5b4be00b1d50 RBX: 0000000002040002 RCX: ff3d5b0a270f2000 [ 2517.878966] RDX: 0000000000000000 RSI: ff3d5b0b021fb9f8 RDI: 0000000000000000 [ 2517.882849] RBP: ff3d5b0b96a6fa00 R08:…