• Peter Wang's avatar
    scsi: ufs: core: Fix deadlock during RTC update · 3911af77
    Peter Wang authored
    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
    
    Skip updating RTC if RPM state is not RPM_ACTIVE.
    
    Fixes: 6bf999e0 ("scsi: ufs: core: Add UFS RTC support")
    Cc: stable@vger.kernel.org # 6.9.x
    Signed-off-by: default avatarPeter Wang <peter.wang@mediatek.com>
    Link: https://lore.kernel.org/r/20240715063831.29792-1-peter.wang@mediatek.comReviewed-by: default avatarBean Huo <beanhuo@micron.com>
    Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    3911af77
ufshcd-priv.h 11.3 KB