BUG: sleeping function called from invalid context in exc_page_fault

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 4e99b321 Merge tag 'nfs-for-5.8-2' of git://git.linux-nfs...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ef589d100000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf3aec367b9ab569
dashboard link: https://syzkaller.appspot.com/bug?extid=aa5151cc1c8abcfa8568
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+aa5151...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1253
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 6825, name: syz-fuzzer
1 lock held by syz-fuzzer/6825:
#0: ffff888098514ba8 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:56 [inline]
#0: ffff888098514ba8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault arch/x86/mm/fault.c:1236 [inline]
#0: ffff888098514ba8 (&mm->mmap_lock#2){++++}-{3:3}, at: handle_page_fault arch/x86/mm/fault.c:1365 [inline]
#0: ffff888098514ba8 (&mm->mmap_lock#2){++++}-{3:3}, at: exc_page_fault+0x3af/0x14c0 arch/x86/mm/fault.c:1418
irq event stamp: 206142
hardirqs last enabled at (206141): [<ffffffff81a2080b>] count_memcg_events include/linux/memcontrol.h:739 [inline]
hardirqs last enabled at (206141): [<ffffffff81a2080b>] count_memcg_event_mm.part.0+0x23b/0x3c0 include/linux/memcontrol.h:760
hardirqs last disabled at (206142): [<ffffffff87e49959>] handle_page_fault arch/x86/mm/fault.c:1373 [inline]
hardirqs last disabled at (206142): [<ffffffff87e49959>] exc_page_fault+0x8b9/0x14c0 arch/x86/mm/fault.c:1418
softirqs last enabled at (206072): [<ffffffff88200748>] __do_softirq+0x748/0xa60 kernel/softirq.c:319
softirqs last disabled at (206061): [<ffffffff88000f0f>] asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
CPU: 0 PID: 6825 Comm: syz-fuzzer Not tainted 5.8.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118
___might_sleep.cold+0x1ef/0x235 kernel/sched/core.c:6875
do_user_addr_fault arch/x86/mm/fault.c:1253 [inline]
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0x3dc/0x14c0 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0010:__prepare_exit_to_usermode+0x0/0x1f0 arch/x86/entry/common.c:234
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a7ec8 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff888096bca000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900016a7f58
RBP: ffffc900016a7f58 R08: 0000000000000001 R09: ffff888098514b3f
R10: 0000000000000000 R11: 1ffff11015139d91 R12: 00007f3c0a2e70a0
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
prepare_exit_to_usermode+0x5/0x30 arch/x86/entry/common.c:277
exc_page_fault+0x8cb/0x14c0 arch/x86/mm/fault.c:1421
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0033:0x42716c
Code: Bad RIP value.
RSP: 002b:000000c000234eb0 EFLAGS: 00010283
RAX: 00007f3c0a2e6020 RBX: 00007f3c0a2e6020 RCX: 00007f3c0a2e7098
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000240
RBP: 000000c000234ed8 R08: 00000000008e70e0 R09: 0000000000000000
R10: 0000000000000034 R11: 0003ffffffffffff R12: 0000000000000000
R13: 000000000000000e R14: 000000000000000e R15: 000000000000000e
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 9f5d0067 P4D 9f5d0067 PUD 96864067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 6825 Comm: syz-fuzzer Tainted: G W 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__prepare_exit_to_usermode+0x0/0x1f0 arch/x86/entry/common.c:234
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a7ec8 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff888096bca000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900016a7f58
RBP: ffffc900016a7f58 R08: 0000000000000001 R09: ffff888098514b3f
R10: 0000000000000000 R11: 1ffff11015139d91 R12: 00007f3c0a2e70a0
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
FS: 000000c000043210(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a8c32000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
prepare_exit_to_usermode+0x5/0x30 arch/x86/entry/common.c:277
exc_page_fault+0x8cb/0x14c0 arch/x86/mm/fault.c:1421
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 9f5d0067 P4D 9f5d0067 PUD 96864067 PMD 0
Oops: 0002 [#2] PREEMPT SMP KASAN
CPU: 0 PID: 6825 Comm: syz-fuzzer Tainted: G W 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:in_gate_area_no_mm+0x0/0x6a arch/x86/entry/vsyscall/vsyscall_64.c:343
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a7408 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffffc900016a74a8 RCX: ffffffff8169f800
RDX: ffff888096bca000 RSI: ffffffff8169f82b RDI: 000000000042716c
RBP: 000000000042716c R08: ffffc900016a75b8 R09: ffffffff8c8c8109
R10: 000000000042716c R11: 0000000000000000 R12: ffffc900016a75b8
R13: 0000000000000001 R14: 000000000042716c R15: ffffc900016a74c8
FS: 000000c000043210(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a8c32000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
is_kernel include/linux/kallsyms.h:43 [inline]
is_ksym_addr include/linux/kallsyms.h:49 [inline]
kallsyms_lookup+0xc3/0x2e0 kernel/kallsyms.c:290
__sprint_symbol+0x9c/0x1c0 kernel/kallsyms.c:363
symbol_string+0x14c/0x370 lib/vsprintf.c:969
pointer+0x185/0x970 lib/vsprintf.c:2226
vsnprintf+0x5b2/0x14f0 lib/vsprintf.c:2624
vscnprintf+0x29/0x80 lib/vsprintf.c:2723
vprintk_store+0x44/0x4a0 kernel/printk/printk.c:1942
vprintk_emit+0x139/0x770 kernel/printk/printk.c:2003
vprintk_func+0x8f/0x1a6 kernel/printk/printk_safe.c:393
printk+0xba/0xed kernel/printk/printk.c:2070
show_ip+0x22/0x30 arch/x86/kernel/dumpstack.c:124
show_iret_regs+0x10/0x32 arch/x86/kernel/dumpstack.c:131
__show_regs+0x18/0x50 arch/x86/kernel/process_64.c:72
show_trace_log_lvl+0x255/0x2b4 arch/x86/kernel/dumpstack.c:274
show_regs arch/x86/kernel/dumpstack.c:447 [inline]
__die_body arch/x86/kernel/dumpstack.c:393 [inline]
__die+0x51/0x90 arch/x86/kernel/dumpstack.c:407
no_context+0x56b/0x9f0 arch/x86/mm/fault.c:695
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault arch/x86/mm/fault.c:1268 [inline]
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xc29/0x14c0 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0010:__prepare_exit_to_usermode+0x0/0x1f0 arch/x86/entry/common.c:234
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a7ec8 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff888096bca000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900016a7f58
RBP: ffffc900016a7f58 R08: 0000000000000001 R09: ffff888098514b3f
R10: 0000000000000000 R11: 1ffff11015139d91 R12: 00007f3c0a2e70a0
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
prepare_exit_to_usermode+0x5/0x30 arch/x86/entry/common.c:277
exc_page_fault+0x8cb/0x14c0 arch/x86/mm/fault.c:1421
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 9f5d0067 P4D 9f5d0067 PUD 96864067 PMD 0
Oops: 0002 [#3] PREEMPT SMP KASAN
CPU: 0 PID: 6825 Comm: syz-fuzzer Tainted: G W 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:in_gate_area_no_mm+0x0/0x6a arch/x86/entry/vsyscall/vsyscall_64.c:343
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a6918 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffffc900016a69b8 RCX: ffffffff8169f800
RDX: ffff888096bca000 RSI: ffffffff8169f82b RDI: 000000000042716c
RBP: 000000000042716c R08: ffffc900016a6ac8 R09: ffff8880ae623da2
R10: 000000000042716c R11: 0000000000000001 R12: ffffc900016a6ac8
R13: 0000000000000001 R14: 000000000042716c R15: ffffc900016a69d8
FS: 000000c000043210(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a8c32000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
is_kernel include/linux/kallsyms.h:43 [inline]
is_ksym_addr include/linux/kallsyms.h:49 [inline]
kallsyms_lookup+0xc3/0x2e0 kernel/kallsyms.c:290
__sprint_symbol+0x9c/0x1c0 kernel/kallsyms.c:363
symbol_string+0x14c/0x370 lib/vsprintf.c:969
pointer+0x185/0x970 lib/vsprintf.c:2226
vsnprintf+0x5b2/0x14f0 lib/vsprintf.c:2624
vscnprintf+0x29/0x80 lib/vsprintf.c:2723
printk_safe_log_store+0xf5/0x250 kernel/printk/printk_safe.c:94
vprintk_safe kernel/printk/printk_safe.c:347 [inline]
vprintk_func+0xef/0x1a6 kernel/printk/printk_safe.c:390
printk+0xba/0xed kernel/printk/printk.c:2070
show_ip+0x22/0x30 arch/x86/kernel/dumpstack.c:124
show_iret_regs+0x10/0x32 arch/x86/kernel/dumpstack.c:131
__show_regs+0x18/0x50 arch/x86/kernel/process_64.c:72
show_trace_log_lvl+0x255/0x2b4 arch/x86/kernel/dumpstack.c:274
show_regs arch/x86/kernel/dumpstack.c:447 [inline]
__die_body arch/x86/kernel/dumpstack.c:393 [inline]
__die+0x51/0x90 arch/x86/kernel/dumpstack.c:407
no_context+0x56b/0x9f0 arch/x86/mm/fault.c:695
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault arch/x86/mm/fault.c:1242 [inline]
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0x946/0x14c0 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0010:in_gate_area_no_mm+0x0/0x6a arch/x86/entry/vsyscall/vsyscall_64.c:343
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0000:ffffc900016a7408 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffffc900016a74a8 RCX: ffffffff8169f800
RDX: ffff888096bca000 RSI: ffffffff8169f82b RDI: 000000000042716c
RBP: 000000000042716c R08: ffffc900016a75b8 R09: ffffffff8c8c8109
R10: 000000000042716c R11: 0000000000000000 R12: ffffc900016a75b8
R13: 0000000000000001 R14: 000000000042716c R15: ffffc900016a74c8
is_kernel include/linux/kallsyms.h:43 [inline]
is_ksym_addr include/linux/kallsyms.h:49 [inline]
kallsyms_lookup+0xc3/0x2e0 kernel/kallsyms.c:290
__sprint_symbol+0x9c/0x1c0 kernel/kallsyms.c:363
symbol_string+0x14c/0x370 lib/vsprintf.c:969
pointer+0x185/0x970 lib/vsprintf.c:2226
vsnprintf+0x5b2/0x14f0 lib/vsprintf.c:2624
vscnprintf+0x29/0x80 lib/vsprintf.c:2723
vprintk_store+0x44/0x4a0 kernel/printk/printk.c:1942
vprintk_emit+0x139/0x770 kernel/printk/printk.c:2003
vprintk_func+0x8f/0x1a6 kernel/printk/printk_safe.c:393
printk+0xba/0xed kernel/printk/printk.c:2070
show_ip+0x22/0x30 arch/x86/kernel/dumpstack.c:124
show_iret_regs+0x10/0x32 arch/x86/kernel/dumpstack.c:131
__show_regs+0x18/0x50 arch/x86/kernel/process_64.c:72
show_trace_log_lvl+0x255/0x2b4 arch/x86/kernel/dumpstack.c:274
show_regs arch/x86/kernel/dumpstack.c:447 [inline]
__die_body arch/x86/kernel/dumpstack.c:393 [inline]
__die+0x51/0x90 arch/x86/kernel/dumpstack.c:407
no_context+0x56b/0x9f0 arch/x86/mm/fault.c:695
__bad_area_nosemaphore+0xa9/0x480 arch/x86/mm/fault.c:789
do_user_addr_fault arch/x86/mm/fault.c:1268 [inline]
handle_page_fault arch/x86/mm/fault.c:1365 [inline]
exc_page_fault+0xc29/0x14c0 arch/x86/mm/fault.c:1418
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0010:__prepare_exit_to_usermode+0x0/0x1f0 arch/x86/entry/common.c:234
Code: 00 00 00 00 00 00 00
Lost 41 message(s)!


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.