Re: [4.18 rc7] BUG: sleeping function called from invalid context at mm/slab.h:421

Hello,

On (08/08/18 11:01), Vlastimil Babka wrote:

On 08/08/2018 05:50 AM, Mikhail Gavrilov wrote:

quoted

Hi guys.
I am catched new bug.
Can anyone look?

fbcon_startup() calls kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL) so
it tells slab it can sleep. The problem must be higher in the stack,
CCing printk people.

Cc-ing fbcon/vt people. I'm not sure I know how exactly console
takeover is expected to work.

printk must be atomic, we can't sleep in console drivers [e.g. printk
from IRQs, etc.]

quoted

[226995.988988] BUG: sleeping function called from invalid context at
mm/slab.h:421
[226995.988988] in_atomic(): 1, irqs_disabled(): 1, pid: 22658, name: gsd-rfkill
[226995.988989] INFO: lockdep is turned off.
[226995.988989] irq event stamp: 0
[226995.988990] hardirqs last  enabled at (0): [<0000000000000000>]
       (null)
[226995.988991] hardirqs last disabled at (0): [<ffffffffa00b6b4a>]
copy_process.part.32+0x72a/0x1e60
[226995.988991] softirqs last  enabled at (0): [<ffffffffa00b6b4a>]
copy_process.part.32+0x72a/0x1e60
[226995.988992] softirqs last disabled at (0): [<0000000000000000>]
       (null)
[226995.988993] CPU: 6 PID: 22658 Comm: gsd-rfkill Tainted: G        W
        4.18.0-0.rc7.git1.1.fc29.x86_64 #1
[226995.988993] Hardware name: Gigabyte Technology Co., Ltd.
Z87M-D3H/Z87M-D3H, BIOS F11 08/12/2014
[226995.988994] Call Trace:
[226995.988994]  dump_stack+0x85/0xc0
[226995.988995]  ___might_sleep.cold.72+0xac/0xbc
[226995.988995]  kmem_cache_alloc_trace+0x202/0x2f0
[226995.988996]  ? fbcon_startup+0xae/0x300
[226995.988996]  fbcon_startup+0xae/0x300
[226995.988997]  do_take_over_console+0x6d/0x180
[226995.988997]  do_fbcon_takeover+0x58/0xb0
[226995.988997]  fbcon_output_notifier.cold.35+0x5/0x23
[226995.988998]  notifier_call_chain+0x39/0x90
[226995.988999]  vt_console_print+0x363/0x420
[226995.988999]  console_unlock+0x422/0x610
[226995.988999]  vprintk_emit+0x268/0x540
[226995.989000]  printk+0x58/0x6f
[226995.989000]  rfkill_fop_release.cold.16+0xc/0x11 [rfkill]
[226995.989001]  __fput+0xc7/0x250
[226995.989001]  task_work_run+0xa1/0xd0
[226995.989002]  exit_to_usermode_loop+0xd8/0xe0
[226995.989002]  do_syscall_64+0x1df/0x1f0
[226995.989003]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

	-ss