Re: [syzbot] [mm?] INFO: task hung in hugetlb_fault

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 87d6aab2389e Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17e11780580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fb6ea01107fa96bd
dashboard link: https://syzkaller.appspot.com/bug?extid=7bb5e48f6ead66c72906
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17dd6327980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d24f9f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/676a1b91b952/disk-87d6aab2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f47965c6cebd/vmlinux-87d6aab2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9ada52fd0e29/bzImage-87d6aab2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7bb5e4...@syzkaller.appspotmail.com

INFO: task syz-executor390:6168 blocked for more than 143 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:28288 pid:6168 tgid:6166 ppid:5217 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
io_schedule+0xbf/0x130 kernel/sched/core.c:7552
folio_wait_bit_common+0x3d8/0x9b0 mm/filemap.c:1309
__folio_lock mm/filemap.c:1647 [inline]
folio_lock include/linux/pagemap.h:1148 [inline]
folio_lock include/linux/pagemap.h:1144 [inline]
__filemap_get_folio+0x6a4/0xaf0 mm/filemap.c:1900
filemap_lock_folio include/linux/pagemap.h:788 [inline]
filemap_lock_hugetlb_folio include/linux/hugetlb.h:795 [inline]
hugetlb_fault+0x16ff/0x2fa0 mm/hugetlb.c:6406
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:58
Code: 40 83 f9 08 73 21 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb
RSP: 0018:ffffc90009107c48 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
RDX: fffff52001220f98 RSI: ffffc90009107cb8 RDI: 000000002001bd48
RBP: 000000002001bd48 R08: 0000000000000000 R09: fffff52001220f97
R10: ffffc90009107cbf R11: 0000000000000000 R12: ffffc90009107cb8
R13: 000000002001bd50 R14: 0000000000000000 R15: 0000000020019680
copy_user_generic arch/x86/include/asm/uaccess_64.h:121 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:142 [inline]
_inline_copy_to_user include/linux/uaccess.h:188 [inline]
_copy_to_user+0xac/0xc0 lib/usercopy.c:26
copy_to_user include/linux/uaccess.h:216 [inline]
msr_read+0x14f/0x250 arch/x86/kernel/msr.c:69
vfs_read+0x1ce/0xbd0 fs/read_write.c:567
ksys_read+0x12f/0x260 fs/read_write.c:712
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ad6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f4df1ba6348 RCX: 00007f4df1b1f8b9
RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000003
RBP: 00007f4df1ba6340 R08: 00007f4df1ad66c0 R09: 00007f4df1ba6348
R10: 00007f4df1ad66c0 R11: 0000000000000246 R12: 00007f4df1ba634c
R13: 0000000000000000 R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6172 blocked for more than 143 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27104 pid:6172 tgid:6166 ppid:5217 flags:0x00000006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlb_wp+0x1b4a/0x3320 mm/hugetlb.c:5894
hugetlb_fault+0x2248/0x2fa0 mm/hugetlb.c:6454
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x60d/0x13f0 arch/x86/mm/fault.c:1338
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f4df1ae75cb
RSP: 002b:00007f4df1ab5170 EFLAGS: 00010246
RAX: 006b6e696c766564 RBX: 00007f4df1ba6358 RCX: 00007f4df1b1f8b9
RDX: d8e7cd4472269fec RSI: 0000000000000000 RDI: 00007f4df1ab55a0
RBP: 00007f4df1ba6350 R08: 00007f4df1ab56c0 R09: 00007f4df1ab56c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4df1ba635c
R13: 000000000000006e R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6171 blocked for more than 143 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:28288 pid:6171 tgid:6167 ppid:5213 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:58
Code: 40 83 f9 08 73 21 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb
RSP: 0018:ffffc90009117c48 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
RDX: fffff52001222f98 RSI: ffffc90009117cb8 RDI: 000000002001b8a0
RBP: 000000002001b8a0 R08: 0000000000000000 R09: fffff52001222f97
R10: ffffc90009117cbf R11: 0000000000000000 R12: ffffc90009117cb8
R13: 000000002001b8a8 R14: 0000000000000000 R15: 0000000020019680
copy_user_generic arch/x86/include/asm/uaccess_64.h:121 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:142 [inline]
_inline_copy_to_user include/linux/uaccess.h:188 [inline]
_copy_to_user+0xac/0xc0 lib/usercopy.c:26
copy_to_user include/linux/uaccess.h:216 [inline]
msr_read+0x14f/0x250 arch/x86/kernel/msr.c:69
vfs_read+0x1ce/0xbd0 fs/read_write.c:567
ksys_read+0x12f/0x260 fs/read_write.c:712
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ad6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f4df1ba6348 RCX: 00007f4df1b1f8b9
RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000003
RBP: 00007f4df1ba6340 R08: 00007f4df1ad66c0 R09: 00007f4df1ba6348
R10: 00007f4df1ad66c0 R11: 0000000000000246 R12: 00007f4df1ba634c
R13: 0000000000000000 R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6174 blocked for more than 144 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27104 pid:6174 tgid:6167 ppid:5213 flags:0x00000006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x60d/0x13f0 arch/x86/mm/fault.c:1338
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f4df1ae75cb
RSP: 002b:00007f4df1ab5170 EFLAGS: 00010246
RAX: 006b6e696c766564 RBX: 00007f4df1ba6358 RCX: 00007f4df1b1f8b9
RDX: d8e7cd4472269fec RSI: 0000000000000000 RDI: 00007f4df1ab55a0
RBP: 00007f4df1ba6350 R08: 00007f4df1ba6358 R09: 00007f4df1ab56c0
R10: 00007f4df1ab56c0 R11: 0000000000000246 R12: 00007f4df1ba635c
R13: 000000000000006e R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6384 blocked for more than 144 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27040 pid:6384 tgid:6383 ppid:5218 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:58
Code: 40 83 f9 08 73 21 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb
RSP: 0018:ffffc90009597c48 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
RDX: fffff520012b2f98 RSI: ffffc90009597cb8 RDI: 000000002001d000
RBP: 000000002001d000 R08: 0000000000000000 R09: fffff520012b2f97
R10: ffffc90009597cbf R11: 0000000000000000 R12: ffffc90009597cb8
R13: 000000002001d008 R14: 0000000000000000 R15: 0000000020019680
copy_user_generic arch/x86/include/asm/uaccess_64.h:121 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:142 [inline]
_inline_copy_to_user include/linux/uaccess.h:188 [inline]
_copy_to_user+0xac/0xc0 lib/usercopy.c:26
copy_to_user include/linux/uaccess.h:216 [inline]
msr_read+0x14f/0x250 arch/x86/kernel/msr.c:69
vfs_read+0x1ce/0xbd0 fs/read_write.c:567
ksys_read+0x12f/0x260 fs/read_write.c:712
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ad6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f4df1ba6348 RCX: 00007f4df1b1f8b9
RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000003
RBP: 00007f4df1ba6340 R08: 00007f4df1ad66c0 R09: 00007f4df1ba6348
R10: 00007f4df1ba6348 R11: 0000000000000246 R12: 00007f4df1ba634c
R13: 0000000000000000 R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6385 blocked for more than 144 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27088 pid:6385 tgid:6383 ppid:5218 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872
vfs_fallocate+0x459/0xf90 fs/open.c:333
ksys_fallocate fs/open.c:356 [inline]
__do_sys_fallocate fs/open.c:364 [inline]
__se_sys_fallocate fs/open.c:362 [inline]
__x64_sys_fallocate+0xd9/0x150 fs/open.c:362
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ab5168 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f4df1ba6358 RCX: 00007f4df1b1f8b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f4df1ba6350 R08: 00007f4df1ab56c0 R09: 00007f4df1ba6358
R10: 0000000000000400 R11: 0000000000000246 R12: 00007f4df1ba635c
R13: 000000000000006e R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6457 blocked for more than 145 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27408 pid:6457 tgid:6453 ppid:5216 flags:0x00000006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872
vfs_fallocate+0x459/0xf90 fs/open.c:333
ksys_fallocate fs/open.c:356 [inline]
__do_sys_fallocate fs/open.c:364 [inline]
__se_sys_fallocate fs/open.c:362 [inline]
__x64_sys_fallocate+0xd9/0x150 fs/open.c:362
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ab5168 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f4df1ba6358 RCX: 00007f4df1b1f8b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f4df1ba6350 R08: 00007f4df1ab56c0 R09: 00007f4df1ba6358
R10: 0000000000000400 R11: 0000000000000246 R12: 00007f4df1ba635c
R13: 000000000000006e R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6501 blocked for more than 145 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27616 pid:6501 tgid:6500 ppid:5215 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
handle_mm_fault+0x930/0xaa0 mm/memory.c:6060
do_user_addr_fault+0x7a3/0x13f0 arch/x86/mm/fault.c:1389
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:58
Code: 40 83 f9 08 73 21 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb
RSP: 0018:ffffc90009567c48 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
RDX: fffff520012acf98 RSI: ffffc90009567cb8 RDI: 000000002001e260
RBP: 000000002001e260 R08: 0000000000000000 R09: fffff520012acf97
R10: ffffc90009567cbf R11: 0000000000000000 R12: ffffc90009567cb8
R13: 000000002001e268 R14: 0000000000000000 R15: 0000000020019680
copy_user_generic arch/x86/include/asm/uaccess_64.h:121 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:142 [inline]
_inline_copy_to_user include/linux/uaccess.h:188 [inline]
_copy_to_user+0xac/0xc0 lib/usercopy.c:26
copy_to_user include/linux/uaccess.h:216 [inline]
msr_read+0x14f/0x250 arch/x86/kernel/msr.c:69
vfs_read+0x1ce/0xbd0 fs/read_write.c:567
ksys_read+0x12f/0x260 fs/read_write.c:712
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ad6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f4df1ba6348 RCX: 00007f4df1b1f8b9
RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000003
RBP: 00007f4df1ba6340 R08: 00007f4df1ad66c0 R09: 00007f4df1ba6348
R10: 00007f4df1ad66c0 R11: 0000000000000246 R12: 00007f4df1ba634c
R13: 0000000000000000 R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>
INFO: task syz-executor390:6502 blocked for more than 145 seconds.
Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor390 state:D stack:27184 pid:6502 tgid:6500 ppid:5215 flags:0x00000006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0xef5/0x5750 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6767
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872
vfs_fallocate+0x459/0xf90 fs/open.c:333
ksys_fallocate fs/open.c:356 [inline]
__do_sys_fallocate fs/open.c:364 [inline]
__se_sys_fallocate fs/open.c:362 [inline]
__x64_sys_fallocate+0xd9/0x150 fs/open.c:362
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4df1b1f8b9
RSP: 002b:00007f4df1ab5168 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f4df1ba6358 RCX: 00007f4df1b1f8b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f4df1ba6350 R08: 00007f4df1ab56c0 R09: 00007f4df1ba6358
R10: 0000000000000400 R11: 0000000000000246 R12: 00007f4df1ba635c
R13: 000000000000006e R14: 00007fff98b1c2f0 R15: 00007fff98b1c3d8
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6720
5 locks held by kworker/u8:8/3033:
1 lock held by klogd/4663:
2 locks held by getty/4978:
#0: ffff88814c4320a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
3 locks held by syz-executor390/6168:
#0: ffff8880614a9498 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
#0: ffff8880614a9498 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:6108 [inline]
#0: ffff8880614a9498 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
#2: ffff88806034b8e8 (&resv_map->rw_sema){++++}-{3:3}, at: hugetlb_vma_lock_read mm/hugetlb.c:276 [inline]
#2: ffff88806034b8e8 (&resv_map->rw_sema){++++}-{3:3}, at: hugetlb_vma_lock_read+0x105/0x140 mm/hugetlb.c:267
2 locks held by syz-executor390/6172:
#0: ffff8880247719b8 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
#0: ffff8880247719b8 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6228
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_wp+0x1b4a/0x3320 mm/hugetlb.c:5894
2 locks held by syz-executor390/6171:
#0: ffff8880614a9e18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
#0: ffff8880614a9e18 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:6099 [inline]
#0: ffff8880614a9e18 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x35/0x6a0 mm/memory.c:6159
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
2 locks held by syz-executor390/6174:
#0: ffff88801d6e7070 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
#0: ffff88801d6e7070 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6228
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
2 locks held by syz-executor390/6384:
#0: ffff8880612e3a98 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
#0: ffff8880612e3a98 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:6108 [inline]
#0: ffff8880612e3a98 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
3 locks held by syz-executor390/6385:
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: ksys_fallocate fs/open.c:356 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __do_sys_fallocate fs/open.c:364 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __se_sys_fallocate fs/open.c:362 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __x64_sys_fallocate+0xd9/0x150 fs/open.c:362
#1: ffff88806270b8f8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#1: ffff88806270b8f8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x2b6/0xfc0 fs/hugetlbfs/inode.c:828
#2: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872
3 locks held by syz-executor390/6457:
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: ksys_fallocate fs/open.c:356 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __do_sys_fallocate fs/open.c:364 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __se_sys_fallocate fs/open.c:362 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __x64_sys_fallocate+0xd9/0x150 fs/open.c:362
#1: ffff888060fa4148 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#1: ffff888060fa4148 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x2b6/0xfc0 fs/hugetlbfs/inode.c:828
#2: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872
2 locks held by syz-executor390/6501:
#0: ffff88807d5a4d98 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
#0: ffff88807d5a4d98 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:6108 [inline]
#0: ffff88807d5a4d98 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159
#1: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x307/0x2fa0 mm/hugetlb.c:6326
3 locks held by syz-executor390/6502:
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: ksys_fallocate fs/open.c:356 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __do_sys_fallocate fs/open.c:364 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __se_sys_fallocate fs/open.c:362 [inline]
#0: ffff8880232a0420 (sb_writers#10){.+.+}-{0:0}, at: __x64_sys_fallocate+0xd9/0x150 fs/open.c:362
#1: ffff8880611b69c8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#1: ffff8880611b69c8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x2b6/0xfc0 fs/hugetlbfs/inode.c:828
#2: ffff8881442d0728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlbfs_fallocate+0x577/0xfc0 fs/hugetlbfs/inode.c:872

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
watchdog+0xf0c/0x1240 kernel/hung_task.c:379
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 3033 Comm: kworker/u8:8 Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
RIP: 0010:lock_acquire.part.0+0x126/0x380 kernel/locking/lockdep.c:5827
Code: 94 c1 6a 00 45 0f b6 c9 ff b4 24 f8 00 00 00 41 57 44 8b 44 24 2c 8b 4c 24 28 e8 a5 ad ff ff 48 c7 c7 40 d3 6c 8b 48 83 c4 28 <e8> 25 23 b7 09 b8 ff ff ff ff 65 0f c1 05 40 d7 97 7e 83 f8 01 0f
RSP: 0018:ffffc90009a577a8 EFLAGS: 00000082
RAX: 0000000000000001 RBX: 1ffff9200134aef6 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8b6cd340
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dc4d88
R10: ffffffff96e26c47 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801b07b078 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a312fe8fd8 CR3: 000000000df7c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
__pte_offset_map_lock+0xf1/0x300 mm/pgtable-generic.c:375
pte_offset_map_lock include/linux/mm.h:3014 [inline]
__get_locked_pte+0x79/0xc0 mm/memory.c:1992
get_locked_pte include/linux/mm.h:2727 [inline]
__text_poke+0x224/0xca0 arch/x86/kernel/alternative.c:1899
text_poke_bp_batch+0x493/0x760 arch/x86/kernel/alternative.c:2373
text_poke_flush arch/x86/kernel/alternative.c:2486 [inline]
text_poke_flush arch/x86/kernel/alternative.c:2483 [inline]
text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2493
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
jump_label_update+0x1d7/0x400 kernel/jump_label.c:920
static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate mm/kfence/core.c:849 [inline]
toggle_allocation_gate+0xfc/0x260 mm/kfence/core.c:841
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.676 msecs


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot has bisected this issue to:

commit 3db978d480e2843979a2b56f2f7da726f2b295b2
Author: Vlastimil Babka <vba...@suse.cz>
Date: Mon Jun 8 04:40:24 2020 +0000

kernel/sysctl: support setting sysctl parameters from kernel command line

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1499efd0580000
start commit: 87d6aab2389e Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=1699efd0580000
console output: https://syzkaller.appspot.com/x/log.txt?x=1299efd0580000

kernel config: https://syzkaller.appspot.com/x/.config?x=fb6ea01107fa96bd
dashboard link: https://syzkaller.appspot.com/bug?extid=7bb5e48f6ead66c72906

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17dd6327980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d24f9f980000

Reported-by: syzbot+7bb5e4...@syzkaller.appspotmail.com
Fixes: 3db978d480e2 ("kernel/sysctl: support setting sysctl parameters from kernel command line")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Vlastimil Babka]

On 10/10/24 11:54 PM, syzbot wrote:
> syzbot has bisected this issue to:
>
> commit 3db978d480e2843979a2b56f2f7da726f2b295b2
> Author: Vlastimil Babka <vba...@suse.cz>
> Date: Mon Jun 8 04:40:24 2020 +0000
>
> kernel/sysctl: support setting sysctl parameters from kernel command line

Hi, I see you have a number of sysctl options in CONFIG_CMDLINE
including sysctl.vm.nr_hugepages=4 which seems necessary to get a
hugetlb_fault. And without the commit above, those sysctl boot options
are not applied. So you'd have to handle sysctl differently to test any
commits earlier than that one.

Thanks,
Vlastimil

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 2ae1ab9934c785b855583e3eabd208d6f3ac91e1
Author: Oscar Salvador <osal...@suse.de>
Date: Mon Jun 30 14:42:08 2025 +0000

mm,hugetlb: change mechanism to detect a COW on private mapping

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1289ea42580000

start commit: 87d6aab2389e Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=fb6ea01107fa96bd
dashboard link: https://syzkaller.appspot.com/bug?extid=7bb5e48f6ead66c72906
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17dd6327980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d24f9f980000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: mm,hugetlb: change mechanism to detect a COW on private mapping