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Add maple I/O Scheduler #12

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bitrvmpd opened this issue May 17, 2018 · 1 comment
Open

Add maple I/O Scheduler #12

bitrvmpd opened this issue May 17, 2018 · 1 comment
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@bitrvmpd
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enhancement New feature or request
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v2.0

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@bitrvmpd
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Let's get rid of CFQ.
@bitrvmpd bitrvmpd added this to the v1.1 milestone May 17, 2018
@bitrvmpd bitrvmpd added the enhancement New feature or request label May 17, 2018
@Pg-Pi3Gey
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FIOPS is also good, If Possible add that too :v

imzf pushed a commit to imzf/android_kernel_xiaomi_msm8937 that referenced this issue Jun 2, 2018
@maurizio-lombardi @gregkh
cdrom: do not call check_disk_change() inside cdrom_open()
0fdfc3f 
[ Upstream commit 2bbea6e117357d17842114c65e9a9cf2d13ae8a3 ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 Loup-ROM#2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 Loup-ROM#3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 Loup-ROM#4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 Loup-ROM#5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 Loup-ROM#6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 Loup-ROM#7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 Loup-ROM#8 [ffff880078447da8] mount_bdev at ffffffff81202570
 Loup-ROM#9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
Loup-ROM#10 [ffff880078447e28] mount_fs at ffffffff81202d09
Loup-ROM#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
Loup-ROM#12 [ffff880078447ea8] do_mount at ffffffff81220fee
Loup-ROM#13 [ffff880078447f28] sys_mount at ffffffff812218d6
Loup-ROM#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 Loup-ROM#2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 Loup-ROM#3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 Loup-ROM#4 [ffff8800784179d0] down_read at ffffffff8168cde0
 Loup-ROM#5 [ffff8800784179e8] get_super at ffffffff81201cc7
 Loup-ROM#6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 Loup-ROM#7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 Loup-ROM#8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 Loup-ROM#9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
Loup-ROM#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
Loup-ROM#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
Loup-ROM#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
Loup-ROM#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
Loup-ROM#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
Loup-ROM#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
Loup-ROM#16 [ffff880078417d00] do_last at ffffffff8120d53d
Loup-ROM#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
Loup-ROM#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
Loup-ROM#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
Loup-ROM#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
@bitrvmpd bitrvmpd self-assigned this Jun 4, 2020
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enhancement New feature or request
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v2.0
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@bitrvmpd @Pg-Pi3Gey