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

[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.kasireddy@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+f1d7fb4f94764243d23e@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.
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 issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
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
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

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

[Kasireddy, Vivek]

> 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.kasireddy@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+f1d7fb4f94764243d23e@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.
> 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 issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> 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
> If you attach or paste a git patch, syzbot will apply it before testing.
> 
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> If you want to undo deduplication, reply with:
> #syz undup

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

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

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+f1d7fb4f94764243d23e@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.

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

[Kasireddy, Vivek]

Hi Andrew,

> 
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger any
> issue:
> 
> Reported-and-tested-by:
> syzbot+f1d7fb4f94764243d23e@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.kasireddy@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.kasireddy@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

> 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.