[syzbot] [fs?] [mm?] INFO: task hung in remove_inode_hugepages

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0b58e108042b Add linux-next specific files for 20240703
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=150453b9980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed034204f2e40e53
dashboard link: https://syzkaller.appspot.com/bug?extid=f1d7fb4f94764243d23e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=130e0685980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16030e6e980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d079762feae/disk-0b58e108.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e53996c8d8c2/vmlinux-0b58e108.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a0bf21cdd844/bzImage-0b58e108.xz

The issue was bisected to:

commit cbe81a753050f5d43ae62da77ff68dcf1d44f9b3
Author: Vivek Kasireddy <vivek.k...@intel.com>
Date: Mon Jun 24 06:36:16 2024 +0000

udmabuf: pin the pages using memfd_pin_folios() API

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13fd687e980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1003687e980000
console output: https://syzkaller.appspot.com/x/log.txt?x=17fd687e980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f1d7fb...@syzkaller.appspotmail.com
Fixes: cbe81a753050 ("udmabuf: pin the pages using memfd_pin_folios() API")

INFO: task syz-executor263:5102 blocked for more than 143 seconds.
Not tainted 6.10.0-rc6-next-20240703-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor263 state:D stack:25984 pid:5102 tgid:5102 ppid:5101 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5248 [inline]
__schedule+0x1800/0x4a60 kernel/sched/core.c:6600
__schedule_loop kernel/sched/core.c:6677 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6692
io_schedule+0x8d/0x110 kernel/sched/core.c:7477
folio_wait_bit_common+0x882/0x12b0 mm/filemap.c:1307
folio_lock include/linux/pagemap.h:1050 [inline]
remove_inode_single_folio fs/hugetlbfs/inode.c:603 [inline]
remove_inode_hugepages+0x508/0x1520 fs/hugetlbfs/inode.c:669
hugetlbfs_evict_inode+0x23/0x70 fs/hugetlbfs/inode.c:689
evict+0x2a8/0x630 fs/inode.c:669
__dentry_kill+0x20d/0x630 fs/dcache.c:603
dput+0x19f/0x2b0 fs/dcache.c:845
__fput+0x5f8/0x8a0 fs/file_table.c:430
task_work_run+0x24f/0x310 kernel/task_work.c:204
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa2f/0x27f0 kernel/exit.c:882
do_group_exit+0x207/0x2c0 kernel/exit.c:1031
__do_sys_exit_group kernel/exit.c:1042 [inline]
__se_sys_exit_group kernel/exit.c:1040 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040
x64_sys_call+0x26e0/0x26e0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f816cea6c09
RSP: 002b:00007fffc0047be8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f816cea6c09
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f816cf212b0 R08: ffffffffffffffb8 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 00007f816cf212b0
R13: 0000000000000000 R14: 00007f816cf21d00 R15: 00007f816ce77e40
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e335860 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:333 [inline]
#0: ffffffff8e335860 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:845 [inline]
#0: ffffffff8e335860 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6704
2 locks held by getty/4858:
#0: ffff88802abbc0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2211
1 lock held by syz-executor263/5102:
#0: ffff88801b2e22a8 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: remove_inode_hugepages+0x38e/0x1520 fs/hugetlbfs/inode.c:664

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc6-next-20240703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x198/0x320 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+0xfee/0x1030 kernel/hung_task.c:379
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 953 Comm: kworker/u8:5 Not tainted 6.10.0-rc6-next-20240703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:236 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x35/0x90 kernel/kcov.c:290
Code: 14 25 40 d7 03 00 65 8b 05 50 50 70 7e a9 00 01 ff 00 74 10 a9 00 01 00 00 74 5b 83 ba 1c 16 00 00 00 74 52 8b 82 f8 15 00 00 <83> f8 03 75 47 48 8b 8a 00 16 00 00 44 8b 8a fc 15 00 00 49 c1 e1
RSP: 0018:ffffc90003f677a8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff888021200000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003f6794c R08: ffffffff8b8dde5e R09: ffffffff8b8db076
R10: 0000000000000002 R11: ffff888021200000 R12: 1ffff920007ecf29
R13: ffffc90003f67920 R14: 1ffff920007ecf2a R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056483a92b600 CR3: 000000000e132000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
insn_get_sib arch/x86/lib/insn.c:447 [inline]
insn_get_displacement+0x2de/0x9a0 arch/x86/lib/insn.c:484
insn_get_immediate+0x62/0x11f0 arch/x86/lib/insn.c:650
insn_get_length arch/x86/lib/insn.c:723 [inline]
insn_decode+0x2d6/0x4c0 arch/x86/lib/insn.c:762
arch_jump_entry_size arch/x86/kernel/jump_label.c:24 [inline]
__jump_label_patch+0xe8/0x490 arch/x86/kernel/jump_label.c:45
arch_jump_label_transform_queue+0x68/0x100 arch/x86/kernel/jump_label.c:137
__jump_label_update+0x177/0x3a0 kernel/jump_label.c:493
static_key_disable_cpuslocked+0xce/0x1c0 kernel/jump_label.c:240
static_key_disable+0x1a/0x20 kernel/jump_label.c:248
toggle_allocation_gate+0x1b8/0x250 mm/kfence/core.c:838
process_one_work kernel/workqueue.c:3224 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3305
worker_thread+0x86d/0xd40 kernel/workqueue.c:3383
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/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: 1.578 msecs


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

[Kasireddy, Vivek]

#syz test: https://gitlab.freedesktop.org/Vivek/drm-tip.git syzbot_fix_remove_inode

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+f1d7fb...@syzkaller.appspotmail.com

Tested on:

commit: 581a87b1 fixup! mm/gup: introduce memfd_pin_folios() f..
git tree: https://gitlab.freedesktop.org/Vivek/drm-tip.git syzbot_fix_remove_inode
console output: https://syzkaller.appspot.com/x/log.txt?x=145a8535980000
kernel config: https://syzkaller.appspot.com/x/.config?x=409b5fcdf33b7555

dashboard link: https://syzkaller.appspot.com/bug?extid=f1d7fb4f94764243d23e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[Kasireddy, Vivek]

Hi Andrew,

>
> Hello,
>
> syzbot has tested the proposed patch and the reproducer did not trigger any
> issue:
>
> Reported-and-tested-by:
> syzbot+f1d7fb...@syzkaller.appspotmail.com
>
> Tested on:
>
> commit: 581a87b1 fixup! mm/gup: introduce memfd_pin_folios() f..
> git tree: https://gitlab.freedesktop.org/Vivek/drm-tip.git
> syzbot_fix_remove_inode

How do you prefer to take the following short fix for this issue?

commit 581a87b19b3739da8c10750b499c55062ea54bf4
Author: Vivek Kasireddy <vivek.k...@intel.com>
Date: Mon Jul 8 23:04:48 2024 -0700

fixup! mm/gup: introduce memfd_pin_folios() for pinning memfd folios

Return -EINVAL if the end offset is greater than the size of memfd.

Signed-off-by: Vivek Kasireddy <vivek.k...@intel.com>

diff --git a/mm/gup.c b/mm/gup.c
index 43f6d2f689d2..54d0dc3831fb 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3630,6 +3630,9 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end,
if (!shmem_file(memfd) && !is_file_hugepages(memfd))
return -EINVAL;

+ if (end >= i_size_read(file_inode(memfd)))
+ return -EINVAL;
+
if (is_file_hugepages(memfd)) {
h = hstate_file(memfd);

Thanks,
Vivek