lkml.org 
[lkml]   [2020]   [Apr]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
Subjectpossible deadlock in shmem_uncharge
From
Hello,

syzbot found the following crash on:

HEAD commit: ae46d2aa mm/gup: Let __get_user_pages_locked() return -EIN..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14a30a77e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=ca75979eeebf06c2
dashboard link: https://syzkaller.appspot.com/bug?extid=c8a8197c8852f566b9d9
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15f5632be00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132ade57e00000

The bug was bisected to:

commit 71725ed10c40696dc6bdccf8e225815dcef24dba
Author: Hugh Dickins <hughd@google.com>
Date: Tue Apr 7 03:07:57 2020 +0000

mm: huge tmpfs: try to split_huge_page() when punching hole

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=120a752be00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=110a752be00000
console output: https://syzkaller.appspot.com/x/log.txt?x=160a752be00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c8a8197c8852f566b9d9@syzkaller.appspotmail.com
Fixes: 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page() when punching hole")

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
5.6.0-syzkaller #0 Not tainted
-----------------------------------------------------
syz-executor428/8337 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff8880a851c778 (&info->lock){....}-{2:2}, at: shmem_uncharge+0x24/0x270 mm/shmem.c:341

and this task is already holding:
ffff8880a851cac8 (&xa->xa_lock#4){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline]
ffff8880a851cac8 (&xa->xa_lock#4){..-.}-{2:2}, at: split_huge_page_to_list+0xad0/0x33b0 mm/huge_memory.c:2864
which would create a new lock dependency:
(&xa->xa_lock#4){..-.}-{2:2} -> (&info->lock){....}-{2:2}

but this new dependency connects a SOFTIRQ-irq-safe lock:
(&xa->xa_lock#4){..-.}-{2:2}

... which became SOFTIRQ-irq-safe at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
test_clear_page_writeback+0x1d7/0x11e0 mm/page-writeback.c:2728
end_page_writeback+0x239/0x520 mm/filemap.c:1317
end_buffer_async_write+0x442/0x5c0 fs/buffer.c:384
end_bio_bh_io_sync+0xe2/0x140 fs/buffer.c:3012
bio_endio+0x473/0x820 block/bio.c:1422
req_bio_endio block/blk-core.c:245 [inline]
blk_update_request+0x3e1/0xdc0 block/blk-core.c:1472
scsi_end_request+0x80/0x7b0 drivers/scsi/scsi_lib.c:575
scsi_io_completion+0x1e7/0x1300 drivers/scsi/scsi_lib.c:959
scsi_softirq_done+0x31e/0x3b0 drivers/scsi/scsi_lib.c:1454
blk_done_softirq+0x2db/0x440 block/blk-softirq.c:37
__do_softirq+0x26c/0x9f7 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x192/0x1d0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:546 [inline]
do_IRQ+0xda/0x270 arch/x86/kernel/irq.c:263
ret_from_intr+0x0/0x2b
arch_local_irq_restore arch/x86/include/asm/paravirt.h:759 [inline]
lock_acquire+0x267/0x8f0 kernel/locking/lockdep.c:4926
down_write+0x8d/0x150 kernel/locking/rwsem.c:1531
inode_lock include/linux/fs.h:797 [inline]
process_measurement+0x68a/0x1750 security/integrity/ima/ima_main.c:228
ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:440
do_open fs/namei.c:3231 [inline]
path_openat+0x1997/0x27d0 fs/namei.c:3346
do_filp_open+0x192/0x260 fs/namei.c:3373
do_sys_openat2+0x585/0x7d0 fs/open.c:1148
do_sys_open+0xc3/0x140 fs/open.c:1164
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3

to a SOFTIRQ-irq-unsafe lock:
(shmlock_user_lock){+.+.}-{2:2}

... which became SOFTIRQ-irq-unsafe at:
...
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:353 [inline]
user_shm_lock+0xab/0x230 mm/mlock.c:855
hugetlb_file_setup+0x4e1/0x677 fs/hugetlbfs/inode.c:1416
newseg+0x460/0xe60 ipc/shm.c:652
ipcget_new ipc/util.c:344 [inline]
ipcget+0xf0/0xcb0 ipc/util.c:643
ksys_shmget ipc/shm.c:742 [inline]
__do_sys_shmget ipc/shm.c:747 [inline]
__se_sys_shmget ipc/shm.c:745 [inline]
__x64_sys_shmget+0x139/0x1a0 ipc/shm.c:745
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3

other info that might help us debug this:

Chain exists of:
&xa->xa_lock#4 --> &info->lock --> shmlock_user_lock

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(shmlock_user_lock);
local_irq_disable();
lock(&xa->xa_lock#4);
lock(&info->lock);
<Interrupt>
lock(&xa->xa_lock#4);

*** DEADLOCK ***

5 locks held by syz-executor428/8337:
#0: ffff8880a7948450 (sb_writers#7){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1655 [inline]
#0: ffff8880a7948450 (sb_writers#7){.+.+}-{0:0}, at: do_sys_ftruncate+0x29f/0x570 fs/open.c:190
#1: ffff8880a851c9d0 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:797 [inline]
#1: ffff8880a851c9d0 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: do_truncate+0x125/0x1f0 fs/open.c:62
#2: ffff8880a851cb90 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:541 [inline]
#2: ffff8880a851cb90 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: split_huge_page_to_list+0x4c3/0x33b0 mm/huge_memory.c:2825
#3: ffff88812ffffcd8 (&pgdat->lru_lock){....}-{2:2}, at: split_huge_page_to_list+0x8da/0x33b0 mm/huge_memory.c:2855
#4: ffff8880a851cac8 (&xa->xa_lock#4){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline]
#4: ffff8880a851cac8 (&xa->xa_lock#4){..-.}-{2:2}, at: split_huge_page_to_list+0xad0/0x33b0 mm/huge_memory.c:2864

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (&xa->xa_lock#4){..-.}-{2:2} {
IN-SOFTIRQ-W at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
test_clear_page_writeback+0x1d7/0x11e0 mm/page-writeback.c:2728
end_page_writeback+0x239/0x520 mm/filemap.c:1317
end_buffer_async_write+0x442/0x5c0 fs/buffer.c:384
end_bio_bh_io_sync+0xe2/0x140 fs/buffer.c:3012
bio_endio+0x473/0x820 block/bio.c:1422
req_bio_endio block/blk-core.c:245 [inline]
blk_update_request+0x3e1/0xdc0 block/blk-core.c:1472
scsi_end_request+0x80/0x7b0 drivers/scsi/scsi_lib.c:575
scsi_io_completion+0x1e7/0x1300 drivers/scsi/scsi_lib.c:959
scsi_softirq_done+0x31e/0x3b0 drivers/scsi/scsi_lib.c:1454
blk_done_softirq+0x2db/0x440 block/blk-softirq.c:37
__do_softirq+0x26c/0x9f7 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x192/0x1d0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:546 [inline]
do_IRQ+0xda/0x270 arch/x86/kernel/irq.c:263
ret_from_intr+0x0/0x2b
arch_local_irq_restore arch/x86/include/asm/paravirt.h:759 [inline]
lock_acquire+0x267/0x8f0 kernel/locking/lockdep.c:4926
down_write+0x8d/0x150 kernel/locking/rwsem.c:1531
inode_lock include/linux/fs.h:797 [inline]
process_measurement+0x68a/0x1750 security/integrity/ima/ima_main.c:228
ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:440
do_open fs/namei.c:3231 [inline]
path_openat+0x1997/0x27d0 fs/namei.c:3346
do_filp_open+0x192/0x260 fs/namei.c:3373
do_sys_openat2+0x585/0x7d0 fs/open.c:1148
do_sys_open+0xc3/0x140 fs/open.c:1164
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
INITIAL USE at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x5b/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:378 [inline]
__add_to_page_cache_locked+0x607/0xe00 mm/filemap.c:855
add_to_page_cache_lru+0x1aa/0x700 mm/filemap.c:921
do_read_cache_page+0x9ab/0x1810 mm/filemap.c:2755
read_mapping_page include/linux/pagemap.h:397 [inline]
read_part_sector+0xf6/0x600 block/partitions/core.c:643
adfspart_check_ICS+0x9d/0xc80 block/partitions/acorn.c:360
check_partition block/partitions/core.c:140 [inline]
blk_add_partitions+0x474/0xe50 block/partitions/core.c:571
bdev_disk_changed+0x1fb/0x380 fs/block_dev.c:1544
__blkdev_get+0xb15/0x1530 fs/block_dev.c:1647
blkdev_get+0x41/0x2b0 fs/block_dev.c:1749
register_disk block/genhd.c:763 [inline]
__device_add_disk+0xa4f/0x1170 block/genhd.c:853
add_disk include/linux/genhd.h:294 [inline]
brd_init+0x297/0x463 drivers/block/brd.c:533
do_one_initcall+0x10a/0x7d0 init/main.c:1158
do_initcall_level init/main.c:1231 [inline]
do_initcalls init/main.c:1247 [inline]
do_basic_setup init/main.c:1267 [inline]
kernel_init_freeable+0x501/0x5ae init/main.c:1451
kernel_init+0xd/0x1bb init/main.c:1358
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
}
... key at: [<ffffffff8c67b1e0>] __key.18007+0x0/0x40
... acquired at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
shmem_uncharge+0x24/0x270 mm/shmem.c:341
__split_huge_page mm/huge_memory.c:2613 [inline]
split_huge_page_to_list+0x274b/0x33b0 mm/huge_memory.c:2886
split_huge_page include/linux/huge_mm.h:204 [inline]
shmem_punch_compound+0x13e/0x1e0 mm/shmem.c:814
shmem_undo_range+0x5f1/0x1b80 mm/shmem.c:870
shmem_truncate_range+0x27/0xa0 mm/shmem.c:980
shmem_setattr+0x8b6/0xc80 mm/shmem.c:1039
notify_change+0xb6d/0x1020 fs/attr.c:336
do_truncate+0x134/0x1f0 fs/open.c:64
do_sys_ftruncate+0x4a5/0x570 fs/open.c:195
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3


the dependencies between the lock to be acquired
and SOFTIRQ-irq-unsafe lock:
-> (shmlock_user_lock){+.+.}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:353 [inline]
user_shm_lock+0xab/0x230 mm/mlock.c:855
hugetlb_file_setup+0x4e1/0x677 fs/hugetlbfs/inode.c:1416
newseg+0x460/0xe60 ipc/shm.c:652
ipcget_new ipc/util.c:344 [inline]
ipcget+0xf0/0xcb0 ipc/util.c:643
ksys_shmget ipc/shm.c:742 [inline]
__do_sys_shmget ipc/shm.c:747 [inline]
__se_sys_shmget ipc/shm.c:745 [inline]
__x64_sys_shmget+0x139/0x1a0 ipc/shm.c:745
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
SOFTIRQ-ON-W at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:353 [inline]
user_shm_lock+0xab/0x230 mm/mlock.c:855
hugetlb_file_setup+0x4e1/0x677 fs/hugetlbfs/inode.c:1416
newseg+0x460/0xe60 ipc/shm.c:652
ipcget_new ipc/util.c:344 [inline]
ipcget+0xf0/0xcb0 ipc/util.c:643
ksys_shmget ipc/shm.c:742 [inline]
__do_sys_shmget ipc/shm.c:747 [inline]
__se_sys_shmget ipc/shm.c:745 [inline]
__x64_sys_shmget+0x139/0x1a0 ipc/shm.c:745
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
INITIAL USE at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:353 [inline]
user_shm_lock+0xab/0x230 mm/mlock.c:855
shmem_lock+0x1dd/0x2d0 mm/shmem.c:2184
shmctl_do_lock+0x73f/0x8f0 ipc/shm.c:1111
ksys_shmctl.constprop.0+0x203/0x350 ipc/shm.c:1188
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
}
... key at: [<ffffffff89a5e858>] shmlock_user_lock+0x18/0x5c0
... acquired at:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:353 [inline]
user_shm_lock+0xab/0x230 mm/mlock.c:855
shmem_lock+0x1dd/0x2d0 mm/shmem.c:2184
shmctl_do_lock+0x73f/0x8f0 ipc/shm.c:1111
ksys_shmctl.constprop.0+0x203/0x350 ipc/shm.c:1188
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3

-> (&info->lock){....}-{2:2} {
INITIAL USE at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x5b/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:378 [inline]
shmem_getpage_gfp+0x937/0x2a10 mm/shmem.c:1882
shmem_getpage mm/shmem.c:154 [inline]
shmem_write_begin+0x102/0x1e0 mm/shmem.c:2483
generic_perform_write+0x20a/0x4e0 mm/filemap.c:3302
__generic_file_write_iter+0x24c/0x610 mm/filemap.c:3431
generic_file_write_iter+0x3f3/0x630 mm/filemap.c:3463
call_write_iter include/linux/fs.h:1907 [inline]
new_sync_write+0x4a2/0x700 fs/read_write.c:483
__vfs_write+0xc9/0x100 fs/read_write.c:496
vfs_write+0x268/0x5d0 fs/read_write.c:558
ksys_write+0x12d/0x250 fs/read_write.c:611
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
}
... key at: [<ffffffff8c667e80>] __key.56422+0x0/0x40
... acquired at:
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
shmem_uncharge+0x24/0x270 mm/shmem.c:341
__split_huge_page mm/huge_memory.c:2613 [inline]
split_huge_page_to_list+0x274b/0x33b0 mm/huge_memory.c:2886
split_huge_page include/linux/huge_mm.h:204 [inline]
shmem_punch_compound+0x13e/0x1e0 mm/shmem.c:814
shmem_undo_range+0x5f1/0x1b80 mm/shmem.c:870
shmem_truncate_range+0x27/0xa0 mm/shmem.c:980
shmem_setattr+0x8b6/0xc80 mm/shmem.c:1039
notify_change+0xb6d/0x1020 fs/attr.c:336
do_truncate+0x134/0x1f0 fs/open.c:64
do_sys_ftruncate+0x4a5/0x570 fs/open.c:195
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3


stack backtrace:
CPU: 0 PID: 8337 Comm: syz-executor428 Not tainted 5.6.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x188/0x20d lib/dump_stack.c:118
print_bad_irq_dependency kernel/locking/lockdep.c:2132 [inline]
check_irq_usage.cold+0x566/0x6de kernel/locking/lockdep.c:2330
check_prev_add kernel/locking/lockdep.c:2519 [inline]
check_prevs_add kernel/locking/lockdep.c:2620 [inline]
validate_chain kernel/locking/lockdep.c:3237 [inline]
__lock_acquire+0x2c39/0x4e00 kernel/locking/lockdep.c:4344
lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
shmem_uncharge+0x24/0x270 mm/shmem.c:341
__split_huge_page mm/huge_memory.c:2613 [inline]
split_huge_page_to_list+0x274b/0x33b0 mm/huge_memory.c:2886
split_huge_page include/linux/huge_mm.h:204 [inline]
shmem_punch_compound+0x13e/0x1e0 mm/shmem.c:814
shmem_undo_range+0x5f1/0x1b80 mm/shmem.c:870
shmem_truncate_range+0x27/0xa0 mm/shmem.c:980
shmem_setattr+0x8b6/0xc80 mm/shmem.c:1039
notify_change+0xb6d/0x1020 fs/attr.c:336
do_truncate+0x134/0x1f0 fs/open.c:64
do_sys_ftruncate+0x4a5/0x570 fs/open.c:195
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x44e769
Code: 4d c9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 1b c9 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe511b3fce8 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00000000006e1c68 RCX: 000000000044e769
RDX: 000000000044e769 RSI: 00000000000001ff RDI: 0000000000000006
RBP: 00000000006e1c60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e1c6c
R13: 00007ffce699f92f R14: 00007fe511b409c0 R15: 0000000000000000


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

\
 
 \ /
  Last update: 2020-04-12 12:12    [W:1.556 / U:0.780 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site