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: 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 This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL. Reported-and-tested-by: syzbot+c2c3302f9c601a4b1be2@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> CC: <stable@xxxxxxxxxxxxxxx> --- [as1940] drivers/usb/misc/yurex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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);
