Re: [BUG] sched: WARNING in __clear_task_blocked_on()

[Vincent Guittot]

Adding John who has a better view of the Android Common Kernel
(android17-6.18) and proxy exex support on it

On Wed, 8 Jul 2026 at 15:51, Jeongho Choi <jh1012.choi@xxxxxxxxxxx> wrote:
>
> Hello,
>
> We are seeing a reproducible kernel panic related to the sched code
> during probe
>
> This issue occurs as a WARNING in the `WARN_ON_ONCE` code of the
> `__clear_task_blocked_on()` function, which immediately triggers a panic
> due to the `panic_on_warn` setting.
>
> Environment:
>
> Architecture: arm64
> Kernel: Linux 6.18.21
> Base: Android Common Kernel (android17-6.18)
> Affected area: include/linux/sched.h
>
> The relevant error/panic log is:
> [    3.107804] [7:       modprobe:  532] WARNING: CPU: 7 PID: 532 at
> include/linux/sched.h:2259 rwsem_mark_wake+0x3d8/0x408
>
> [    3.108951] [7:       modprobe:  532] CPU: 7 UID: 0 PID: 532 Comm:
> modprobe Tainted: G           OE
> 6.18.21-android17-5-ga1a8e8cab9ec-4k #1 PREEMPT
> e0006e62dcbab4e76968dae147108b649e8f2b88
>
> [    3.109033] [7:       modprobe:  532] pstate: a34020c5 (NzCv daIF
> +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
> [    3.109044] [7:       modprobe:  532] pc :
> rwsem_mark_wake+0x3d8/0x408
> [    3.109048] [7:       modprobe:  532] lr :
> rwsem_mark_wake+0x1bc/0x408
> [    3.109050] [7:       modprobe:  532] sp : ffffffc096a031d0
> [    3.109052] [7:       modprobe:  532] x29: ffffffc096a031f0 x28:
> ffffffe95bb97d98 x27: 000000001dd00000
> [    3.109072] [7:       modprobe:  532] x26: ffffffc095693a20 x25:
> ffffffc096a031d8 x24: ffffffffffffffff
> [    3.109076] [7:       modprobe:  532] x23: 0000000000000000 x22:
> ffffffc096a031d8 x21: ffffff88021ebd80
> [    3.109081] [7:       modprobe:  532] x20: ffffff88001062a8 x19:
> ffffffc096a03240 x18: ffffffe95adce240
> [    3.109087] [7:       modprobe:  532] x17: 00000000c66b5183 x16:
> 00000000c66b5183 x15: 0000000000000001
> [    3.109091] [7:       modprobe:  532] x14: fffffffffe000000 x13:
> ffffff88055beb58 x12: 0000000000000000
> [    3.109096] [7:       modprobe:  532] x11: 0000000000000008 x10:
> 0000000000000001 x9 : 0000000000000003
> [    3.109101] [7:       modprobe:  532] x8 : ffffff8800106269 x7 :
> 7f7f7f7f7f7f7f7f x6 : fefefeff71646b6f
> [    3.109105] [7:       modprobe:  532] x5 : 8080808000000000 x4 :
> 0000000000000020 x3 : 0000000072656c70
> [    3.109110] [7:       modprobe:  532] x2 : ffffffc096a031d8 x1 :
> 0000000000000000 x0 : ffffff88021ec7c0
> [    3.109124] [7:       modprobe:  532] Call trace:
> [    3.109142] [7:       modprobe:  532]  rwsem_mark_wake+0x3d8/0x408
> (P)
> [    3.109157] [7:       modprobe:  532]  up_write+0xa8/0x14c
> [    3.109165] [7:       modprobe:  532]  kernfs_link_sibling+0xd8/0x16c
> [    3.109199] [7:       modprobe:  532]  kernfs_add_one+0x84/0x154
> [    3.109223] [7:       modprobe:  532]
> kernfs_create_dir_ns+0xc0/0x104
> [    3.109227] [7:       modprobe:  532]  sysfs_create_dir_ns+0x80/0xf8
> [    3.109231] [7:       modprobe:  532]
> kobject_add_internal+0xc0/0x2e0
> [    3.109240] [7:       modprobe:  532]  kobject_add+0x90/0x100
> [    3.109243] [7:       modprobe:  532]
> class_dir_create_and_add+0x7c/0xec
> [    3.109270] [7:       modprobe:  532]  get_device_parent+0xb4/0x148
> [    3.109274] [7:       modprobe:  532]  device_add+0x74/0x884
> [    3.109277] [7:       modprobe:  532]
> device_create_groups_vargs+0xd0/0x164
> [    3.109352] [7:       modprobe:  532]  device_create+0x58/0x80
> [    3.109355] [7:       modprobe:  532]
> ***_create+0x1f4/0x4d8
> [    3.110504] [7:       modprobe:  532]
> ***_probe+0x1ac/0x2f8
> [    3.110594] [7:       modprobe:  532]
> ***_module_register_client_module+0xa8/0x118
> [    3.111616] [7:       modprobe:  532]
> ***_driver_register+0x3c/0x50
> [    3.111763] [7:       modprobe:  532]  init_module+0x50/0xf30
> [    3.111824] [7:       modprobe:  532]  do_one_initcall+0xdc/0x374
> [    3.111861] [7:       modprobe:  532]  do_init_module+0x60/0x4b4
> [    3.111889] [7:       modprobe:  532]  load_module+0x2a74/0x2cd0
> [    3.111899] [7:       modprobe:  532]
> __arm64_sys_finit_module+0x230/0x31c
> [    3.111901] [7:       modprobe:  532]  invoke_syscall+0x58/0xe4
> [    3.111929] [7:       modprobe:  532]  do_el0_svc+0x48/0xdc
> [    3.111937] [7:       modprobe:  532]  el0_svc+0x3c/0x98
> [    3.111982] [7:       modprobe:  532]
> el0t_64_sync_handler+0x20/0x130
> [    3.111985] [7:       modprobe:  532]  el0t_64_sync+0x1c4/0x1c8
>
>
>
> The code at the WARN location mentioned in the log above is as follows.
>
> 2249 static inline void __clear_task_blocked_on(struct task_struct *p,
>  void *m)
> 2250 {
> 2251         /* Currently we serialize blocked_on under the
>  task::blocked_lock */
> 2252         lockdep_assert_held_once(&p->blocked_lock);
> 2253         /*
> 2254          * There may be cases where we re-clear already
>  cleared
> 2255          * blocked_on relationships, but make sure we are
>  not
> 2256          * clearing the relationship with a different lock.
> 2257          */
> 2258         WARN_ON_ONCE(m && p->blocked_on.lock &&
> 2259                      p->blocked_on.lock != m &&
>  p->blocked_on.lock != PROXY_WAKING);
>
>
> Additionally, I have discovered the following patches in the current 7.2
> mainline kernel that have not been applied to the 6.18.21 kernel.
> Could these patches be related to the current WARNING issue?
>
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/sched.h?h=v7.2-rc2&id=f13beb010e4ab0735c9e46802cbcc820a8bd6467
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/sched.h?h=v7.2-rc2&id=4c2a20413d7fb3fc3dd7adf233a4f82bb203fb58
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/sched.h?h=v7.2-rc2&id=1628b25248d0742b2ce9c7cfa59cd183e35f37e1
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/sched.h?h=v7.2-rc2&id=ec9d4f1c424134bbf30965075df78d02a5d021dc
>
> 2262se review this issue.
> Thanks,
> Jeongho Choi
>