On Sun, Jun 5, 2016 at 1:32 PM, <mchristi@xxxxxxxxxx> wrote: > From: Mike Christie <mchristi@xxxxxxxxxx> > > The req operation REQ_OP is separated from the rq_flag_bits > definition. This converts the block layer drivers to > use req_op to get the op from the request struct. > > Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx> > --- > drivers/block/loop.c | 6 +++--- > drivers/block/mtip32xx/mtip32xx.c | 2 +- > drivers/block/nbd.c | 2 +- > drivers/block/rbd.c | 4 ++-- > drivers/block/xen-blkfront.c | 8 +++++--- > drivers/ide/ide-floppy.c | 2 +- > drivers/md/dm.c | 2 +- > drivers/mmc/card/block.c | 7 +++---- > drivers/mmc/card/queue.c | 6 ++---- Dave Chinner reported a deadlock with XFS + DAX, which I reproduced and bisected to this commit: commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34 Author: Mike Christie <mchristi@xxxxxxxxxx> Date: Sun Jun 5 14:32:17 2016 -0500 drivers: use req op accessor Here are the steps to reproduce the deadlock with a BRD ramdisk: mkfs.xfs -f /dev/ram0 mount -o dax /dev/ram0 /mnt/scratch xfs_io -f -c "truncate 1g" /mnt/scratch/test.img losetup -f --show /mnt/scratch/test.img mkfs.xfs -f /dev/loop0 At this point the mkfs.xfs deadlocks. Here is the stack trace gathered via "echo w > /proc/sysrq-trigger" and passed through kasan_symbolize.py: brd: module loaded XFS (ram0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk XFS (ram0): Mounting V5 Filesystem XFS (ram0): Ending clean mount sysrq: SysRq : Show Blocked State task PC stack pid father mkfs.xfs D ffff88060ae47b38 0 1482 1287 0x00000000 ffff88060ae47b38 00000000000079e8 ffff880610fd8d98 ffff880036011a40 ffff8800aa6dcec0 ffff88060ae48000 ffff880610fd8d80 7fffffffffffffff ffff8800aa6dcec0 00000000024000c0 ffff88060ae47b50 ffffffff81aca775 Call Trace: [<ffffffff81aca775>] schedule+0x35/0x80 kernel/sched/core.c:3360 [<ffffffff81acf431>] schedule_timeout+0x271/0x460 kernel/time/timer.c:1493 [<ffffffff81ac9c34>] io_schedule_timeout+0xa4/0x110 kernel/sched/core.c:4969 [< inline >] do_wait_for_common kernel/sched/completion.c:75 [< inline >] __wait_for_common kernel/sched/completion.c:93 [< inline >] wait_for_common_io kernel/sched/completion.c:107 [<ffffffff81acb33f>] wait_for_completion_io+0xdf/0x120 kernel/sched/completion.c:155 [<ffffffff81573206>] submit_bio_wait+0x66/0x90 block/bio.c:870 [<ffffffff81588016>] blkdev_issue_discard+0x86/0xc0 block/blk-lib.c:115 [<ffffffff8158ea23>] blk_ioctl_discard+0xa3/0xd0 block/ioctl.c:221 [<ffffffff8158f5da>] blkdev_ioctl+0x60a/0x9e0 block/ioctl.c:510 [<ffffffff812bddb3>] block_ioctl+0x43/0x50 fs/block_dev.c:1714 [< inline >] vfs_ioctl fs/ioctl.c:43 [<ffffffff8128ec72>] do_vfs_ioctl+0xa2/0x6a0 fs/ioctl.c:674 [< inline >] SYSC_ioctl fs/ioctl.c:689 [<ffffffff8128f2e9>] SyS_ioctl+0x79/0x90 fs/ioctl.c:680 [<ffffffff81ad0abc>] entry_SYSCALL_64_fastpath+0x1f/0xbd arch/x86/entry/entry_64.S:207 The line numbers are for the commit above, not for linux/master. This occurs 100% as of this commit, and 0% with the previous commit. This doesn't occur if you don't use DAX, but based on the content of the commit I'm guessing that difference is due to variations in the way the two paths use discard. - Ross -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
