Re: [syzbot] KASAN: use-after-free Read in snd_pcm_post_stop

[syzbot <syzbot+e29d28728f38190cecfc@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in __io_req_task_work_add

------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at io_uring/refs.h:31 req_ref_get io_uring/refs.h:31 [inline]
WARNING: CPU: 1 PID: 0 at io_uring/refs.h:31 __io_req_task_work_add+0x763/0x850 io_uring/io_uring.c:1310
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.2.0-rc3-next-20230112-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:req_ref_get io_uring/refs.h:31 [inline]
RIP: 0010:__io_req_task_work_add+0x763/0x850 io_uring/io_uring.c:1310
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 e6 00 00 00 49 8b 7c 24 18 be 01 00 00 00 e8 e7 28 57 fd e9 00 fe ff ff e8 cd 73 80 fd <0f> 0b e9 fd f9 ff ff e8 c1 73 80 fd 0f 0b e9 56 fa ff ff e8 b5 73
RSP: 0018:ffffc900001e0a48 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880711ba8c0 RCX: 0000000000000100
RDX: ffff88813feb9d40 RSI: ffffffff84014913 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000005 R12: ffff88807e836000
R13: ffff8880711ba920 R14: ffff88801cfd4c00 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f00038cf5a8 CR3: 0000000027f59000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 io_req_task_work_add io_uring/io_uring.h:95 [inline]
 __io_poll_execute io_uring/poll.c:366 [inline]
 io_poll_wake+0x243/0x600 io_uring/poll.c:441
 __wake_up_common+0x147/0x650 kernel/sched/wait.c:107
 __wake_up_common_lock+0xd4/0x140 kernel/sched/wait.c:138
 snd_pcm_update_state+0x445/0x510 sound/core/pcm_lib.c:204
 snd_pcm_update_hw_ptr0+0xada/0x1af0 sound/core/pcm_lib.c:465
 snd_pcm_period_elapsed_under_stream_lock+0x156/0x220 sound/core/pcm_lib.c:1817
 snd_pcm_period_elapsed+0x2c/0x50 sound/core/pcm_lib.c:1849
 dummy_hrtimer_callback+0x98/0x1b0 sound/drivers/dummy.c:385
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x600/0xcf0 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x17f/0x360 kernel/time/hrtimer.c:1766
 __do_softirq+0x1fb/0xaf6 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:113 [inline]
RIP: 0010:acpi_idle_do_entry+0x1fd/0x2a0 drivers/acpi/processor_idle.c:570
Code: 89 de e8 36 39 7b f7 84 db 75 ac e8 bd 3c 7b f7 e8 38 bd 81 f7 66 90 e8 b1 3c 7b f7 0f 00 2d 2a 44 ab 00 e8 a5 3c 7b f7 fb f4 <9c> 5b 81 e3 00 02 00 00 fa 31 ff 48 89 de e8 60 39 7b f7 48 85 db
RSP: 0018:ffffc90000177d10 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88813feb9d40 RSI: ffffffff8a06803b RDI: 0000000000000000
RBP: ffff888012684864 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001
R13: ffff888012684800 R14: ffff888012684864 R15: ffff88801c228004
 acpi_idle_enter+0x368/0x510 drivers/acpi/processor_idle.c:707
 cpuidle_enter_state+0x1af/0xd40 drivers/cpuidle/cpuidle.c:239
 cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:356
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:236 [inline]
 do_idle+0x3f7/0x590 kernel/sched/idle.c:303
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:400
 start_secondary+0x256/0x300 arch/x86/kernel/smpboot.c:264
 secondary_startup_64_no_verify+0xce/0xdb
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 de                	mov    %ebx,%esi
   2:	e8 36 39 7b f7       	callq  0xf77b393d
   7:	84 db                	test   %bl,%bl
   9:	75 ac                	jne    0xffffffb7
   b:	e8 bd 3c 7b f7       	callq  0xf77b3ccd
  10:	e8 38 bd 81 f7       	callq  0xf781bd4d
  15:	66 90                	xchg   %ax,%ax
  17:	e8 b1 3c 7b f7       	callq  0xf77b3ccd
  1c:	0f 00 2d 2a 44 ab 00 	verw   0xab442a(%rip)        # 0xab444d
  23:	e8 a5 3c 7b f7       	callq  0xf77b3ccd
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	9c                   	pushfq <-- trapping instruction
  2b:	5b                   	pop    %rbx
  2c:	81 e3 00 02 00 00    	and    $0x200,%ebx
  32:	fa                   	cli
  33:	31 ff                	xor    %edi,%edi
  35:	48 89 de             	mov    %rbx,%rsi
  38:	e8 60 39 7b f7       	callq  0xf77b399d
  3d:	48 85 db             	test   %rbx,%rbx


Tested on:

commit:         0a093b28 Add linux-next specific files for 20230112
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=17d091ee480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=835f3591019836d5
dashboard link: https://syzkaller.appspot.com/bug?extid=e29d28728f38190cecfc
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1100ada1480000