• Chen Yu's avatar
    PM: hibernate: Do not get block device exclusively in test_resume mode · 5904de0d
    Chen Yu authored
    The system refused to do a test_resume because it found that the
    swap device has already been taken by someone else. Specifically,
    the swsusp_check()->blkdev_get_by_dev(FMODE_EXCL) is supposed to
    do this check.
    
    Steps to reproduce:
     dd if=/dev/zero of=/swapfile bs=$(cat /proc/meminfo |
           awk '/MemTotal/ {print $2}') count=1024 conv=notrunc
     mkswap /swapfile
     swapon /swapfile
     swap-offset /swapfile
     echo 34816 > /sys/power/resume_offset
     echo test_resume > /sys/power/disk
     echo disk > /sys/power/state
    
     PM: Using 3 thread(s) for compression
     PM: Compressing and saving image data (293150 pages)...
     PM: Image saving progress:   0%
     PM: Image saving progress:  10%
     ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
     ata1.00: configured for UDMA/100
     ata2: SATA link down (SStatus 0 SControl 300)
     ata5: SATA link down (SStatus 0 SControl 300)
     ata6: SATA link down (SStatus 0 SControl 300)
     ata3: SATA link down (SStatus 0 SControl 300)
     ata4: SATA link down (SStatus 0 SControl 300)
     PM: Image saving progress:  20%
     PM: Image saving progress:  30%
     PM: Image saving progress:  40%
     PM: Image saving progress:  50%
     pcieport 0000:00:02.5: pciehp: Slot(0-5): No device found
     PM: Image saving progress:  60%
     PM: Image saving progress:  70%
     PM: Image saving progress:  80%
     PM: Image saving progress:  90%
     PM: Image saving done
     PM: hibernation: Wrote 1172600 kbytes in 2.70 seconds (434.29 MB/s)
     PM: S|
     PM: hibernation: Basic memory bitmaps freed
     PM: Image not found (code -16)
    
    This is because when using the swapfile as the hibernation storage,
    the block device where the swapfile is located has already been mounted
    by the OS distribution(usually mounted as the rootfs). This is not
    an issue for normal hibernation, because software_resume()->swsusp_check()
    happens before the block device(rootfs) mount. But it is a problem for the
    test_resume mode. Because when test_resume happens, the block device has
    been mounted already.
    
    Thus remove the FMODE_EXCL for test_resume mode. This would not be a
    problem because in test_resume stage, the processes have already been
    frozen, and the race condition described in
    Commit 39fbef4b ("PM: hibernate: Get block device exclusively in swsusp_check()")
    is unlikely to happen.
    
    Fixes: 39fbef4b ("PM: hibernate: Get block device exclusively in swsusp_check()")
    Reported-by: default avatarYifan Li <yifan2.li@intel.com>
    Suggested-by: default avatarPavankumar Kondeti <quic_pkondeti@quicinc.com>
    Tested-by: default avatarPavankumar Kondeti <quic_pkondeti@quicinc.com>
    Tested-by: default avatarWendy Wang <wendy.wang@intel.com>
    Signed-off-by: default avatarChen Yu <yu.c.chen@intel.com>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    5904de0d
swap.c 37.9 KB