Description

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: mcq: Fix &hwq->cq_lock deadlock issue When ufshcd_err_handler() is executed, CQ event interrupt can enter waiting for the same lock. This can happen in ufshcd_handle_mcq_cq_events() and also in ufs_mtk_mcq_intr(). The following warning message will be generated when &hwq->cq_lock is used in IRQ context with IRQ enabled. Use ufshcd_mcq_poll_cqe_lock() with spin_lock_irqsave instead of spin_lock to resolve the deadlock issue. [name:lockdep&]WARNING: inconsistent lock state [name:lockdep&]-------------------------------- [name:lockdep&]inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. [name:lockdep&]kworker/u16:4/260 [HC0[0]:SC0[0]:HE1:SE1] takes: ffffff8028444600 (&hwq->cq_lock){?.-.}-{2:2}, at: ufshcd_mcq_poll_cqe_lock+0x30/0xe0 [name:lockdep&]{IN-HARDIRQ-W} state was registered at: lock_acquire+0x17c/0x33c _raw_spin_lock+0x5c/0x7c ufshcd_mcq_poll_cqe_lock+0x30/0xe0 ufs_mtk_mcq_intr+0x60/0x1bc [ufs_mediatek_mod] __handle_irq_event_percpu+0x140/0x3ec handle_irq_event+0x50/0xd8 handle_fasteoi_irq+0x148/0x2b0 generic_handle_domain_irq+0x4c/0x6c gic_handle_irq+0x58/0x134 call_on_irq_stack+0x40/0x74 do_interrupt_handler+0x84/0xe4 el1_interrupt+0x3c/0x78 <snip> Possible unsafe locking scenario: CPU0 ---- lock(&hwq->cq_lock); <Interrupt> lock(&hwq->cq_lock); *** DEADLOCK *** 2 locks held by kworker/u16:4/260: [name:lockdep&] stack backtrace: CPU: 7 PID: 260 Comm: kworker/u16:4 Tainted: G S W OE 6.1.17-mainline-android14-2-g277223301adb #1 Workqueue: ufs_eh_wq_0 ufshcd_err_handler Call trace: dump_backtrace+0x10c/0x160 show_stack+0x20/0x30 dump_stack_lvl+0x98/0xd8 dump_stack+0x20/0x60 print_usage_bug+0x584/0x76c mark_lock_irq+0x488/0x510 mark_lock+0x1ec/0x25c __lock_acquire+0x4d8/0xffc lock_acquire+0x17c/0x33c _raw_spin_lock+0x5c/0x7c ufshcd_mcq_poll_cqe_lock+0x30/0xe0 ufshcd_poll+0x68/0x1b0 ufshcd_transfer_req_compl+0x9c/0xc8 ufshcd_err_handler+0x3bc/0xea0 process_one_work+0x2f4/0x7e8 worker_thread+0x234/0x450 kthread+0x110/0x134 ret_from_fork+0x10/0x20

References 2

• git.kernel.org https://git.kernel.org/stable/c/2ce8c49c7b53e0a2258b833eeab16a6d78f732d1
• git.kernel.org https://git.kernel.org/stable/c/948afc69615167a3c82430f99bfd046332b89912

Remediation