Re: [syzbot] [block?] general protection fault in bio_alloc_bioset

[Vasily Gorbik]

On Sat, Mar 21, 2026 at 05:18:01PM -0700, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> SYZFAIL: failed to recv rpc
> 
> SYZFAIL: failed to recv rpc
> fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)
> 
> 
> Tested on:
> 
> commit:         785f0eb2 Add linux-next specific files for 20260320
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1385ccba580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=22bf3527036b9be1
> dashboard link: https://syzkaller.appspot.com/bug?extid=09ddb593eea76a158f42
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=143881d6580000

Well, keeping in mind that the repro does

ioctl$BLKTRACESETUP(r1, 0xc0481273, &(0x7f00000001c0)={'\x00', 0x1, 0x18148795, 0x7, 0x6})

that is roughly 2.6 GiB per CPU of relay buffer on an ~8 GiB VM with tiny
swap. Surviving 1h15m before syzbot loses it is about as good as it gets.