On 12/2/21 17:47, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: c4bc515d73b5 usb: dwc2: gadget: use existing helper
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=12c7d311b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=1fa54650ce78e6dc
dashboard link: https://syzkaller.appspot.com/bug?extid=cce1ee31614c171f5595
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cce1ee31614c171f5595@xxxxxxxxxxxxxxxxxxxxxxxxx
------------[ cut here ]------------
raw_local_irq_restore() called with IRQs enabled
WARNING: CPU: 1 PID: 1206 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Modules linked in:
CPU: 1 PID: 1206 Comm: dhcpcd Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
Code: d3 ff cc cc cc cc cc cc cc cc cc cc cc 80 3d e7 4e dc 02 00 74 01 c3 48 c7 c7 a0 85 27 86 c6 05 d6 4e dc 02 01 e8 fd 13 d3 ff <0f> 0b c3 44 8b 05 75 05 e7 02 55 53 65 48 8b 1c 25 80 6f 02 00 45
RSP: 0018:ffffc90000f0f6a8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000000
RDX: ffff8881100f1c00 RSI: ffffffff812bae78 RDI: fffff520001e1ec7
RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff812b4c4e R11: 0000000000000000 R12: ffff88814b2047c0
R13: 0000000000000000 R14: 0000000000000000 R15: 00000000ffffffff
FS: 00007f0d4252e740(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd8c7ba7718 CR3: 0000000117bd2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rtl92cu_hw_init.cold+0x119f/0x34c5 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c:1003
I think I understand this warning:
The routine in question is the following comment and code:
/* As this function can take a very long time (up to 350 ms)
* and can be called with irqs disabled, reenable the irqs
* to let the other devices continue being serviced.
*
* It is safe doing so since our own interrupts will only be enabled
* in a subsequent step.
*/
local_save_flags(flags);
local_irq_enable();
...
exit:
local_irq_restore(flags);
return err;
It seems to me that this would lead to the "raw_local_irq_restore() called with
IRQs enabled" warning.
A brute-force method would be to insert a "local_irq_disable()" call just before
the local_irq_restore() call. Would that work? Is there a more elegant solution?
Thanks,
Larry
