Re: sound: unable to handle kernel paging request snd_seq_prioq_cell_out
On Mon, Feb 6, 2017 at 3:24 PM, Takashi Iwai wrote:
> On Tue, 31 Jan 2017 11:04:46 +0100,
> Dmitry Vyukov wrote:
>>
>> Hello,
>>
>> The following program triggers wild memory access in snd_seq_prioq_cell_out:
>> https://gist.githubusercontent.com/dvyukov/e0bfb47caf577217b3b0550866cba00b/raw/111473e99109fc96a1d3e252c3b8f982e8eaa265/gistfile1.txt
>>
>> BUG: unable to handle kernel paging request at c9000392ddb8
>> IP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
>> PGD 6cc6f067
>> PUD 6cc70067
>> PMD 5f94c067
>> PTE 0
>> Oops: [#1] SMP KASAN
>> Modules linked in:
>> CPU: 2 PID: 375 Comm: syz-executor Not tainted 4.10.0-rc5+ #201
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> task: 880066f92500 task.stack: 88005f74
>> RIP: 0010:snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
>> RSP: 0018:88005f7470b8 EFLAGS: 00010046
>> RAX: dc00 RBX: 11000bee8e18 RCX: c9c22000
>> RDX: 192000725bb7 RSI: 8348787e RDI: c9000392ddb8
>> RBP: 88005f747208 R08: 0001 R09: 0001
>> R10: dc00 R11: 0004 R12: 8800673cbe80
>> R13: 88005f7471e0 R14: c9000392dd90 R15: 8800673cbe98
>> FS: 7f5262fee700() GS:88006d10() knlGS:
>> CS: 0010 DS: ES: CR0: 80050033
>> CR2: c9000392ddb8 CR3: 66209000 CR4: 001406e0
>> Call Trace:
>> snd_seq_prioq_delete+0x8b/0xf0 sound/core/seq/seq_prioq.c:90
>> queue_delete+0x77/0xb0 sound/core/seq/seq_queue.c:152
>> snd_seq_queue_client_leave+0x34/0x130 sound/core/seq/seq_queue.c:595
>> seq_free_client1.part.5+0x10a/0x410 sound/core/seq/seq_clientmgr.c:258
>> seq_free_client1 sound/core/seq/seq_clientmgr.c:255 [inline]
>> seq_free_client+0x6f/0x170 sound/core/seq/seq_clientmgr.c:284
>> snd_seq_release+0x51/0xe0 sound/core/seq/seq_clientmgr.c:366
>> __fput+0x332/0x7f0 fs/file_table.c:208
>> fput+0x15/0x20 fs/file_table.c:244
>> task_work_run+0x18a/0x260 kernel/task_work.c:116
>> get_signal+0x148f/0x1820 kernel/signal.c:2143
>> do_signal+0xd2/0x2190 arch/x86/kernel/signal.c:807
>> exit_to_usermode_loop+0x200/0x2a0 arch/x86/entry/common.c:156
>> prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
>> syscall_return_slowpath+0x4d3/0x570 arch/x86/entry/common.c:259
>> entry_SYSCALL_64_fastpath+0xc0/0xc2
>> RIP: 0033:0x4457d9
>> RSP: 002b:7f5262fedb58 EFLAGS: 0286 ORIG_RAX: 0010
>> RAX: RBX: 007080a8 RCX: 004457d9
>> RDX: 20001000 RSI: 4058534c RDI: 0005
>> RBP: 2250 R08: R09:
>> R10: R11: 0286 R12: 006e0310
>> R13: 0005 R14: 4058534c R15: 20001000
>> Code: f6 0f 84 90 00 00 00 e8 02 1e 2a fe 49 8d 7e 28 48 b8 00 00 00
>> 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1f 01 00 00 <49>
>> 8b 46 28 49 8d 7c 24 08 48 89 fa 49 89 04 24 48 c1 ea 03 48
>> RIP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
>> RSP: 88005f7470b8
>> CR2: c9000392ddb8
>> ---[ end trace cbaec69c4a9fdbfc ]---
>>
>> On commit fd694aaa46c7ed811b72eb47d5eb11ce7ab3f7f1 (Jan 26).
>
> This is due to a forced resource release after the loop timeout.
> You must have seen a message like
> ALSA: snd_seq_pool_done timeout: 1 cells remain
> before the Oops.
Yes, there are such messages.
Applied locally for testing. Thanks!
> Below is a simple fix. I'm going to queue it to for-linus branch.
>
>
> thanks,
>
> Takashi
>
> -- 8< --
> From: Takashi Iwai
> Subject: [PATCH] ALSA: seq: Don't handle loop timeout at snd_seq_pool_done()
>
> snd_seq_pool_done() syncs with closing of all opened threads, but it
> aborts the wait loop with a timeout, and proceeds to the release
> resource even if not all threads have been closed. The timeout was 5
> seconds, and if you run a crazy stuff, it can exceed easily, and may
> result in the access of the invalid memory address -- this is what
> syzkaller detected in a bug report.
>
> As a fix, let the code graduate from naiveness, simply remove the loop
> timeout.
>
> BugLink:
> http://lkml.kernel.org/r/cact4y+ydhdv2h5llzdtjdvf-qiyhuhhtraw4rbb4guhtcqb...@mail.gmail.com
> Reported-by: Dmitry Vyukov
> Cc:
> Signed-off-by: Takashi Iwai
> ---
> sound/core/seq/seq_memory.c | 9 +
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c
> index c850345c43b5..dfa5156f3585 100644
> --- a/sound/core/seq/seq_memory.c
> +++ b/sound/core/seq/seq_memory.c
> @@ -419,7 +419,6 @@ int snd_seq_pool_done(struct snd_seq_pool *pool)
> {
> unsigned long flags;
> struct snd_seq_event_cell *ptr;
> - int max_count = 5 * HZ;
>
> if (snd_BUG_ON(!pool))
> return -EINVAL;
> @@ -432,14 +431,8 @@ int snd
Re: sound: unable to handle kernel paging request snd_seq_prioq_cell_out
On Tue, 31 Jan 2017 11:04:46 +0100,
Dmitry Vyukov wrote:
>
> Hello,
>
> The following program triggers wild memory access in snd_seq_prioq_cell_out:
> https://gist.githubusercontent.com/dvyukov/e0bfb47caf577217b3b0550866cba00b/raw/111473e99109fc96a1d3e252c3b8f982e8eaa265/gistfile1.txt
>
> BUG: unable to handle kernel paging request at c9000392ddb8
> IP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
> PGD 6cc6f067
> PUD 6cc70067
> PMD 5f94c067
> PTE 0
> Oops: [#1] SMP KASAN
> Modules linked in:
> CPU: 2 PID: 375 Comm: syz-executor Not tainted 4.10.0-rc5+ #201
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> task: 880066f92500 task.stack: 88005f74
> RIP: 0010:snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
> RSP: 0018:88005f7470b8 EFLAGS: 00010046
> RAX: dc00 RBX: 11000bee8e18 RCX: c9c22000
> RDX: 192000725bb7 RSI: 8348787e RDI: c9000392ddb8
> RBP: 88005f747208 R08: 0001 R09: 0001
> R10: dc00 R11: 0004 R12: 8800673cbe80
> R13: 88005f7471e0 R14: c9000392dd90 R15: 8800673cbe98
> FS: 7f5262fee700() GS:88006d10() knlGS:
> CS: 0010 DS: ES: CR0: 80050033
> CR2: c9000392ddb8 CR3: 66209000 CR4: 001406e0
> Call Trace:
> snd_seq_prioq_delete+0x8b/0xf0 sound/core/seq/seq_prioq.c:90
> queue_delete+0x77/0xb0 sound/core/seq/seq_queue.c:152
> snd_seq_queue_client_leave+0x34/0x130 sound/core/seq/seq_queue.c:595
> seq_free_client1.part.5+0x10a/0x410 sound/core/seq/seq_clientmgr.c:258
> seq_free_client1 sound/core/seq/seq_clientmgr.c:255 [inline]
> seq_free_client+0x6f/0x170 sound/core/seq/seq_clientmgr.c:284
> snd_seq_release+0x51/0xe0 sound/core/seq/seq_clientmgr.c:366
> __fput+0x332/0x7f0 fs/file_table.c:208
> fput+0x15/0x20 fs/file_table.c:244
> task_work_run+0x18a/0x260 kernel/task_work.c:116
> get_signal+0x148f/0x1820 kernel/signal.c:2143
> do_signal+0xd2/0x2190 arch/x86/kernel/signal.c:807
> exit_to_usermode_loop+0x200/0x2a0 arch/x86/entry/common.c:156
> prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
> syscall_return_slowpath+0x4d3/0x570 arch/x86/entry/common.c:259
> entry_SYSCALL_64_fastpath+0xc0/0xc2
> RIP: 0033:0x4457d9
> RSP: 002b:7f5262fedb58 EFLAGS: 0286 ORIG_RAX: 0010
> RAX: RBX: 007080a8 RCX: 004457d9
> RDX: 20001000 RSI: 4058534c RDI: 0005
> RBP: 2250 R08: R09:
> R10: R11: 0286 R12: 006e0310
> R13: 0005 R14: 4058534c R15: 20001000
> Code: f6 0f 84 90 00 00 00 e8 02 1e 2a fe 49 8d 7e 28 48 b8 00 00 00
> 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1f 01 00 00 <49>
> 8b 46 28 49 8d 7c 24 08 48 89 fa 49 89 04 24 48 c1 ea 03 48
> RIP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231
> RSP: 88005f7470b8
> CR2: c9000392ddb8
> ---[ end trace cbaec69c4a9fdbfc ]---
>
> On commit fd694aaa46c7ed811b72eb47d5eb11ce7ab3f7f1 (Jan 26).
This is due to a forced resource release after the loop timeout.
You must have seen a message like
ALSA: snd_seq_pool_done timeout: 1 cells remain
before the Oops.
Below is a simple fix. I'm going to queue it to for-linus branch.
thanks,
Takashi
-- 8< --
From: Takashi Iwai
Subject: [PATCH] ALSA: seq: Don't handle loop timeout at snd_seq_pool_done()
snd_seq_pool_done() syncs with closing of all opened threads, but it
aborts the wait loop with a timeout, and proceeds to the release
resource even if not all threads have been closed. The timeout was 5
seconds, and if you run a crazy stuff, it can exceed easily, and may
result in the access of the invalid memory address -- this is what
syzkaller detected in a bug report.
As a fix, let the code graduate from naiveness, simply remove the loop
timeout.
BugLink:
http://lkml.kernel.org/r/cact4y+ydhdv2h5llzdtjdvf-qiyhuhhtraw4rbb4guhtcqb...@mail.gmail.com
Reported-by: Dmitry Vyukov
Cc:
Signed-off-by: Takashi Iwai
---
sound/core/seq/seq_memory.c | 9 +
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c
index c850345c43b5..dfa5156f3585 100644
--- a/sound/core/seq/seq_memory.c
+++ b/sound/core/seq/seq_memory.c
@@ -419,7 +419,6 @@ int snd_seq_pool_done(struct snd_seq_pool *pool)
{
unsigned long flags;
struct snd_seq_event_cell *ptr;
- int max_count = 5 * HZ;
if (snd_BUG_ON(!pool))
return -EINVAL;
@@ -432,14 +431,8 @@ int snd_seq_pool_done(struct snd_seq_pool *pool)
if (waitqueue_active(&pool->output_sleep))
wake_up(&pool->output_sleep);
- while (atomic_read(&pool->counter) > 0) {
- if (max_count == 0) {
- pr_warn("ALSA
sound: unable to handle kernel paging request snd_seq_prioq_cell_out
Hello, The following program triggers wild memory access in snd_seq_prioq_cell_out: https://gist.githubusercontent.com/dvyukov/e0bfb47caf577217b3b0550866cba00b/raw/111473e99109fc96a1d3e252c3b8f982e8eaa265/gistfile1.txt BUG: unable to handle kernel paging request at c9000392ddb8 IP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231 PGD 6cc6f067 PUD 6cc70067 PMD 5f94c067 PTE 0 Oops: [#1] SMP KASAN Modules linked in: CPU: 2 PID: 375 Comm: syz-executor Not tainted 4.10.0-rc5+ #201 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: 880066f92500 task.stack: 88005f74 RIP: 0010:snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231 RSP: 0018:88005f7470b8 EFLAGS: 00010046 RAX: dc00 RBX: 11000bee8e18 RCX: c9c22000 RDX: 192000725bb7 RSI: 8348787e RDI: c9000392ddb8 RBP: 88005f747208 R08: 0001 R09: 0001 R10: dc00 R11: 0004 R12: 8800673cbe80 R13: 88005f7471e0 R14: c9000392dd90 R15: 8800673cbe98 FS: 7f5262fee700() GS:88006d10() knlGS: CS: 0010 DS: ES: CR0: 80050033 CR2: c9000392ddb8 CR3: 66209000 CR4: 001406e0 Call Trace: snd_seq_prioq_delete+0x8b/0xf0 sound/core/seq/seq_prioq.c:90 queue_delete+0x77/0xb0 sound/core/seq/seq_queue.c:152 snd_seq_queue_client_leave+0x34/0x130 sound/core/seq/seq_queue.c:595 seq_free_client1.part.5+0x10a/0x410 sound/core/seq/seq_clientmgr.c:258 seq_free_client1 sound/core/seq/seq_clientmgr.c:255 [inline] seq_free_client+0x6f/0x170 sound/core/seq/seq_clientmgr.c:284 snd_seq_release+0x51/0xe0 sound/core/seq/seq_clientmgr.c:366 __fput+0x332/0x7f0 fs/file_table.c:208 fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x18a/0x260 kernel/task_work.c:116 get_signal+0x148f/0x1820 kernel/signal.c:2143 do_signal+0xd2/0x2190 arch/x86/kernel/signal.c:807 exit_to_usermode_loop+0x200/0x2a0 arch/x86/entry/common.c:156 prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline] syscall_return_slowpath+0x4d3/0x570 arch/x86/entry/common.c:259 entry_SYSCALL_64_fastpath+0xc0/0xc2 RIP: 0033:0x4457d9 RSP: 002b:7f5262fedb58 EFLAGS: 0286 ORIG_RAX: 0010 RAX: RBX: 007080a8 RCX: 004457d9 RDX: 20001000 RSI: 4058534c RDI: 0005 RBP: 2250 R08: R09: R10: R11: 0286 R12: 006e0310 R13: 0005 R14: 4058534c R15: 20001000 Code: f6 0f 84 90 00 00 00 e8 02 1e 2a fe 49 8d 7e 28 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1f 01 00 00 <49> 8b 46 28 49 8d 7c 24 08 48 89 fa 49 89 04 24 48 c1 ea 03 48 RIP: snd_seq_prioq_cell_out+0x11d/0x260 sound/core/seq/seq_prioq.c:231 RSP: 88005f7470b8 CR2: c9000392ddb8 ---[ end trace cbaec69c4a9fdbfc ]--- On commit fd694aaa46c7ed811b72eb47d5eb11ce7ab3f7f1 (Jan 26).
