CVE-2026-43448: Undefined Security Weakness

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

nvme-pci: Fix race bug in nvme_poll_irqdisable()

In the following scenario, pdev can be disabled between (1) and (3) by (2). This sets pdev->msix_enabled = 0. Then, pci_irq_vector() will return MSI-X IRQ(>15) for (1) whereas return INTx IRQ(<=15) for (2). This causes IRQ warning because it tries to enable INTx IRQ that has never been disabled before.

To fix this, save IRQ number into a local variable and ensure disable_irq() and enable_irq() operate on the same IRQ number. Even if pci_free_irq_vectors() frees the IRQ concurrently, disable_irq() and enable_irq() on a stale IRQ number is still valid and safe, and the depth accounting reamins balanced.

task 1: nvme_poll_irqdisable() disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(1) enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(3)

task 2: nvme_reset_work() nvme_dev_disable() pdev->msix_enable = 0; ...(2)

crash log:

------------[ cut here ]------------ Unbalanced enable for IRQ 10 WARNING: kernel/irq/manage.c:753 at __enable_irq+0x102/0x190 kernel/irq/manage.c:753, CPU#1: kworker/1:0H/26 Modules linked in: CPU: 1 UID: 0 PID: 26 Comm: kworker/1:0H Not tainted 6.19.0-dirty #9 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: kblockd blk_mq_timeout_work RIP: 0010:__enable_irq+0x107/0x190 kernel/irq/manage.c:753 Code: ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 79 48 8d 3d 2e 7a 3f 05 41 8b 74 24 2c <67> 48 0f b9 3a e8 ef b9 21 00 5b 41 5c 5d e9 46 54 66 03 e8 e1 b9 RSP: 0018:ffffc900001bf550 EFLAGS: 00010046 RAX: 0000000000000007 RBX: 0000000000000000 RCX: ffffffffb20c0e90 RDX: 0000000000000000 RSI: 000000000000000a RDI: ffffffffb74b88f0 RBP: ffffc900001bf560 R08: ffff88800197cf00 R09: 0000000000000001 R10: 0000000000000003 R11: 0000000000000003 R12: ffff8880012a6000 R13: 1ffff92000037eae R14: 000000000000000a R15: 0000000000000293 FS: 0000000000000000(0000) GS:ffff8880b49f7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555da4a25fa8 CR3: 00000000208e8000 CR4: 00000000000006f0 Call Trace: <TASK> enable_irq+0x121/0x1e0 kernel/irq/manage.c:797 nvme_poll_irqdisable+0x162/0x1c0 drivers/nvme/host/pci.c:1494 nvme_timeout+0x965/0x14b0 drivers/nvme/host/pci.c:1744 blk_mq_rq_timed_out block/blk-mq.c:1653 [inline] blk_mq_handle_expired+0x227/0x2d0 block/blk-mq.c:1721 bt_iter+0x2fc/0x3a0 block/blk-mq-tag.c:292 __sbitmap_for_each_set include/linux/sbitmap.h:269 [inline] sbitmap_for_each_set include/linux/sbitmap.h:290 [inline] bt_for_each block/blk-mq-tag.c:324 [inline] blk_mq_queue_tag_busy_iter+0x969/0x1e80 block/blk-mq-tag.c:536 blk_mq_timeout_work+0x627/0x870 block/blk-mq.c:1763 process_one_work+0x956/0x1aa0 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x65c/0xe60 kernel/workqueue.c:3421 kthread+0x41a/0x930 kernel/kthread.c:463 ret_from_fork+0x6f8/0x8c0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> irq event stamp: 74478 hardirqs last enabled at (74477): [<ffffffffb5720a9c>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] hardirqs last enabled at (74477): [<ffffffffb5720a9c>] _raw_spin_unlock_irq+0x2c/0x60 kernel/locking/spinlock.c:202 hardirqs last disabled at (74478): [<ffffffffb57207b5>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (74478): [<ffffffffb57207b5>] _raw_spin_lock_irqsave+0x85/0xa0 kernel/locking/spinlock.c:162 softirqs last enabled at (74304): [<ffffffffb1e9466c>] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (74304): [<ffffffffb1e9466c>] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (74304): [<ffffffffb1e9466c>] __irq_exit_rcu+0xdc/0x120 ---truncated---