WARNING in slab_pre_alloc_hook

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 449dc8c9 Merge tag 'for-v5.9' of git://git.kernel.org/pub/..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=16581652900000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ef84fa8ee48e528
dashboard link: https://syzkaller.appspot.com/bug?extid=c2c3302f9c601a4b1be2
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e8de34900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1244eb62900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c2c330...@syzkaller.appspotmail.com

------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<00000000370c7c68>] prepare_to_wait+0xb1/0x2a0 kernel/sched/wait.c:247
WARNING: CPU: 1 PID: 340 at kernel/sched/core.c:7253 __might_sleep+0x135/0x190 kernel/sched/core.c:7253
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 340 Comm: syz-executor677 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xf6/0x16e lib/dump_stack.c:118
panic+0x2aa/0x6e1 kernel/panic.c:231
__warn.cold+0x20/0x50 kernel/panic.c:600
report_bug+0x1bd/0x210 lib/bug.c:198
handle_bug+0x41/0x80 arch/x86/kernel/traps.c:234
exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:__might_sleep+0x135/0x190 kernel/sched/core.c:7253
Code: 65 48 8b 1c 25 40 ef 01 00 48 8d 7b 10 48 89 fe 48 c1 ee 03 80 3c 06 00 75 2b 48 8b 73 10 48 c7 c7 e0 9e 06 86 e8 ed 12 f6 ff <0f> 0b e9 46 ff ff ff e8 1f b2 4b 00 e9 29 ff ff ff e8 15 b2 4b 00
RSP: 0018:ffff8881cdb77a28 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881c6458000 RCX: 0000000000000000
RDX: ffff8881c6458000 RSI: ffffffff8129ec93 RDI: ffffed1039b6ef37
RBP: ffffffff86fdade2 R08: 0000000000000001 R09: ffff8881db32f54f
R10: 0000000000000000 R11: 0000000030343354 R12: 00000000000001f2
R13: 0000000000000000 R14: 0000000000000068 R15: ffffffff83c1b1aa
slab_pre_alloc_hook.constprop.0+0xea/0x200 mm/slab.h:498
slab_alloc_node mm/slub.c:2816 [inline]
slab_alloc mm/slub.c:2900 [inline]
kmem_cache_alloc_trace+0x46/0x220 mm/slub.c:2917
kmalloc include/linux/slab.h:554 [inline]
dummy_urb_enqueue+0x7a/0x880 drivers/usb/gadget/udc/dummy_hcd.c:1251
usb_hcd_submit_urb+0x2b2/0x22d0 drivers/usb/core/hcd.c:1547
usb_submit_urb+0xb4e/0x13e0 drivers/usb/core/urb.c:570
yurex_write+0x3ea/0x820 drivers/usb/misc/yurex.c:495
vfs_write+0x2b0/0x730 fs/read_write.c:576
ksys_write+0x12d/0x250 fs/read_write.c:631
do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x444809
Code: e8 bc af 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 9b d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc4c2b1358 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444809
RDX: 00000000000000cb RSI: 0000000020000300 RDI: 0000000000000004
RBP: 00000000006cf018 R08: 000000000000000f R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402430
R13: 00000000004024c0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[Alan Stern]

The yurex driver shouldn't use GFP_KERNEL in a context where the current
state isn't TASK_RUNNING.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 449dc8c9

Index: usb-devel/drivers/usb/misc/yurex.c
===================================================================
--- usb-devel.orig/drivers/usb/misc/yurex.c
+++ usb-devel/drivers/usb/misc/yurex.c
@@ -492,7 +492,7 @@ static ssize_t yurex_write(struct file *
prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE);
dev_dbg(&dev->interface->dev, "%s - submit %c\n", __func__,
dev->cntl_buffer[0]);
- retval = usb_submit_urb(dev->cntl_urb, GFP_KERNEL);
+ retval = usb_submit_urb(dev->cntl_urb, GFP_ATOMIC);
if (retval >= 0)
timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
finish_wait(&dev->waitq, &wait);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+c2c330...@syzkaller.appspotmail.com

Tested on:

commit: 449dc8c9 Merge tag 'for-v5.9' of git://git.kernel.org/pub/..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git

kernel config: https://syzkaller.appspot.com/x/.config?x=6ef84fa8ee48e528
dashboard link: https://syzkaller.appspot.com/bug?extid=c2c3302f9c601a4b1be2
compiler: gcc (GCC) 10.1.0-syz 20200507

patch: https://syzkaller.appspot.com/x/patch.diff?x=14ef8e52900000

Note: testing is done by a robot and is best-effort only.

[Alan Stern]

The syzbot fuzzer identified a bug in the yurex driver: It passes
GFP_KERNEL as a memory-allocation flag to usb_submit_urb() at a time
when its state is TASK_INTERRUPTIBLE, not TASK_RUNNING:

This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL.

Reported-and-tested-by: syzbot+c2c330...@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
CC: <sta...@vger.kernel.org>

---


[as1940]


drivers/usb/misc/yurex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)