[PATCH v2] ufs: core: fix deadlock when rtc update

[Martin K. Petersen]

On Mon, 15 Jul 2024 14:38:31 +0800, peter.wang at mediatek.com wrote:

> There is a deadlock when runtime suspend waits for the flush of RTC work,
> and the RTC work calls ufshcd_rpm_get_sync to wait for runtime resume.
> 
> Here is deadlock backtrace
> kworker/0:1     D 4892.876354 10 10971 4859 0x4208060 0x8 10 0 120 670730152367
> ptr            f0ffff80c2e40000 0 1 0x00000001 0x000000ff 0x000000ff 0x000000ff
> <ffffffee5e71ddb0> __switch_to+0x1a8/0x2d4
> <ffffffee5e71e604> __schedule+0x684/0xa98
> <ffffffee5e71ea60> schedule+0x48/0xc8
> <ffffffee5e725f78> schedule_timeout+0x48/0x170
> <ffffffee5e71fb74> do_wait_for_common+0x108/0x1b0
> <ffffffee5e71efe0> wait_for_completion+0x44/0x60
> <ffffffee5d6de968> __flush_work+0x39c/0x424
> <ffffffee5d6decc0> __cancel_work_sync+0xd8/0x208
> <ffffffee5d6dee2c> cancel_delayed_work_sync+0x14/0x28
> <ffffffee5e2551b8> __ufshcd_wl_suspend+0x19c/0x480
> <ffffffee5e255fb8> ufshcd_wl_runtime_suspend+0x3c/0x1d4
> <ffffffee5dffd80c> scsi_runtime_suspend+0x78/0xc8
> <ffffffee5df93580> __rpm_callback+0x94/0x3e0
> <ffffffee5df90b0c> rpm_suspend+0x2d4/0x65c
> <ffffffee5df91448> __pm_runtime_suspend+0x80/0x114
> <ffffffee5dffd95c> scsi_runtime_idle+0x38/0x6c
> <ffffffee5df912f4> rpm_idle+0x264/0x338
> <ffffffee5df90f14> __pm_runtime_idle+0x80/0x110
> <ffffffee5e24ce44> ufshcd_rtc_work+0x128/0x1e4
> <ffffffee5d6e3a40> process_one_work+0x26c/0x650
> <ffffffee5d6e65c8> worker_thread+0x260/0x3d8
> <ffffffee5d6edec8> kthread+0x110/0x134
> <ffffffee5d616b18> ret_from_fork+0x10/0x20
> 
> [...]

Applied to 6.11/scsi-queue, thanks!

[1/1] ufs: core: fix deadlock when rtc update
      https://git.kernel.org/mkp/scsi/c/3911af778f20

-- 
Martin K. Petersen	Oracle Linux Engineering