[kernel?] BUG: scheduling while atomic in print_tainted

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 033c40a89f55 Merge tag 'apparmor-v6.2-rc9' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15c628c8c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=f36d77a88a56f28f
dashboard link: https://syzkaller.appspot.com/bug?extid=2954935ad581bb2fdf6a
compiler: arm-linux-gnueabi-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm
CC: [daniel...@ffwll.ch del...@gmx.de gre...@linuxfoundation.org ilpo.j...@linux.intel.com jiri...@kernel.org linux-...@vger.kernel.org]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+295493...@syzkaller.appspotmail.com

BUG: scheduling while atomic: syz-executor.0/30462/0x00000002
Modules linked in:
Preemption disabled at:
[<8091f5b8>] gsmld_write+0x30/0x90 drivers/tty/n_gsm.c:3410
Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ...
CPU: 0 PID: 30462 Comm: syz-executor.0 Not tainted 6.2.0-rc8-syzkaller #0
Hardware name: ARM-Versatile Express
Backtrace:
[<817aaf48>] (dump_backtrace) from [<817ab03c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:256)
r7:81d7c8f8 r6:82422a84 r5:60000093 r4:81d8af0c
[<817ab024>] (show_stack) from [<817c74d0>] (__dump_stack lib/dump_stack.c:88 [inline])
[<817ab024>] (show_stack) from [<817c74d0>] (dump_stack_lvl+0x48/0x54 lib/dump_stack.c:106)
[<817c7488>] (dump_stack_lvl) from [<817c74f4>] (dump_stack+0x18/0x1c lib/dump_stack.c:113)
r5:00000000 r4:8264bd14
[<817c74dc>] (dump_stack) from [<817abbe4>] (panic+0x11c/0x360 kernel/panic.c:318)
[<817abac8>] (panic) from [<80241600>] (print_tainted+0x0/0xa0 kernel/panic.c:238)
r3:8240c488 r2:00000001 r1:81d7f4f0 r0:81d7c8f8
r7:822abfc0
[<8024157c>] (check_panic_on_warn) from [<8027524c>] (__schedule_bug+0x88/0x9c kernel/sched/core.c:5836)
[<802751c4>] (__schedule_bug) from [<817ca534>] (schedule_debug kernel/sched/core.c:5865 [inline])
[<802751c4>] (__schedule_bug) from [<817ca534>] (__schedule+0x8fc/0xad8 kernel/sched/core.c:6500)
r5:dddd4fc0 r4:00000000
[<817c9c38>] (__schedule) from [<817ca76c>] (schedule+0x5c/0xac kernel/sched/core.c:6682)
r10:00000000 r9:00000000 r8:00000000 r7:00000002 r6:82429bc4 r5:8291e780
r4:8291e780
[<817ca710>] (schedule) from [<817d11ac>] (schedule_timeout+0xd0/0x108 kernel/time/timer.c:2143)
r5:8291e780 r4:7fffffff
[<817d10dc>] (schedule_timeout) from [<817cd4fc>] (___down_common kernel/locking/semaphore.c:225 [inline])
[<817d10dc>] (schedule_timeout) from [<817cd4fc>] (__down_common+0x108/0x2cc kernel/locking/semaphore.c:246)
r6:82429bc4 r5:8291e780 r4:7fffffff
[<817cd3f4>] (__down_common) from [<817cd6d8>] (__down+0x18/0x1c kernel/locking/semaphore.c:254)
r9:84112b40 r8:00000000 r7:a0000013 r6:84daee00 r5:00000000 r4:82429bc4
[<817cd6c0>] (__down) from [<817cd728>] (down+0x4c/0x60 kernel/locking/semaphore.c:63)
[<817cd6dc>] (down) from [<802add18>] (console_lock+0x14/0x38 kernel/printk/printk.c:2658)
r4:00000000
[<802add04>] (console_lock) from [<80931978>] (do_con_write+0x84/0x2028 drivers/tty/vt/vt.c:2908)
[<809318f4>] (do_con_write) from [<8093395c>] (con_write+0x14/0x28 drivers/tty/vt/vt.c:3295)
r10:00000000 r9:84112b40 r8:00000000 r7:a0000013 r6:843e9980 r5:84daee00
r4:84daee00
[<80933948>] (con_write) from [<8091f5e4>] (gsmld_write+0x5c/0x90 drivers/tty/n_gsm.c:3413)
r5:00000000 r4:84daee00
[<8091f588>] (gsmld_write) from [<80910eb8>] (do_tty_write drivers/tty/tty_io.c:1018 [inline])
[<8091f588>] (gsmld_write) from [<80910eb8>] (file_tty_write.constprop.0+0x13c/0x2bc drivers/tty/tty_io.c:1089)
r9:84112b40 r8:eb4f1ef0 r7:00000000 r6:84daee00 r5:00000000 r4:00000000
[<80910d7c>] (file_tty_write.constprop.0) from [<809110e0>] (tty_write+0x14/0x18 drivers/tty/tty_io.c:1110)
r10:00004007 r9:8291e780 r8:00000000 r7:eb4f1f68 r6:00000000 r5:84112b40
r4:809110cc
[<809110cc>] (tty_write) from [<804b9860>] (call_write_iter include/linux/fs.h:2189 [inline])
[<809110cc>] (tty_write) from [<804b9860>] (new_sync_write fs/read_write.c:491 [inline])
[<809110cc>] (tty_write) from [<804b9860>] (vfs_write+0x2c4/0x3bc fs/read_write.c:584)
[<804b959c>] (vfs_write) from [<804b9ac0>] (ksys_write+0x68/0xec fs/read_write.c:637)
r10:00000004 r9:8291e780 r8:80200288 r7:00000000 r6:00000000 r5:84112b40
r4:84112b41
[<804b9a58>] (ksys_write) from [<804b9b54>] (__do_sys_write fs/read_write.c:649 [inline])
[<804b9a58>] (ksys_write) from [<804b9b54>] (sys_write+0x10/0x14 fs/read_write.c:646)
r7:00000004 r6:0014c2b8 r5:00000000 r4:00000000
[<804b9b44>] (sys_write) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:66)
Exception stack(0xeb4f1fa8 to 0xeb4f1ff0)
1fa0: 00000000 00000000 00000003 00000000 00000000 00000000
1fc0: 00000000 00000000 0014c2b8 00000004 7ee363d2 76b0c6d0 7ee36544 76b0c20c
1fe0: 76b0c020 76b0c010 00016fec 0004dfa0
Rebooting in 86400 seconds..


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[syzbot]

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