Re: [syzbot] [trace?] general protection fault in mtree_load

[Jiri Olsa <olsajiri@gmail.com>]

On Mon, Jun 22, 2026 at 03:04:16PM +0200, Oleg Nesterov wrote:
> On 06/21, syzbot wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    6b5a2b7d9bc1 Merge tag 'trace-tools-v7.2' of git://git.ker..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=16d56986580000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=ea6584355d75e0cd
> > dashboard link: https://syzkaller.appspot.com/bug?extid=61ce80689253f42e6d80
> > compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > Downloadable assets:
> > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6b5a2b7d.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/b3cb0499fbe9/vmlinux-6b5a2b7d.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/47cfbe57f6ea/bzImage-6b5a2b7d.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+61ce80689253f42e6d80@syzkaller.appspotmail.com
> >
> > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] SMP KASAN NOPTI
> > KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
> > CPU: 3 UID: 0 PID: 24402 Comm: syz.4.5217 Tainted: G             L      syzkaller #0 PREEMPT(full)
> > Tainted: [L]=SOFTLOCKUP
> > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> > RIP: 0010:mas_root lib/maple_tree.c:759 [inline]
> > RIP: 0010:mas_start lib/maple_tree.c:1179 [inline]
> > RIP: 0010:mtree_load+0x16d/0xa90 lib/maple_tree.c:5657
> > Code: 00 00 00 00 48 c7 44 24 78 ff ff ff ff e8 6b bd 84 f6 48 8b 5c 24 50 c6 84 24 9c 00 00 00 00 48 8d 7b 48 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 d6 08 00 00 48 8b 5b 48 e8 6f 1a 08 00 31 ff
> > RSP: 0018:ffffc900039c76d8 EFLAGS: 00010206
> > RAX: 0000000000000011 RBX: 0000000000000040 RCX: ffffffff8b848746
> > RDX: ffff888041b6a540 RSI: ffffffff8b848775 RDI: 0000000000000088
> > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001
> > R10: 0000000000000001 R11: 000000000000751b R12: dffffc0000000000
> > R13: ffff88802693adc0 R14: 00001fff904365a7 R15: dffffc0000000000
> > FS:  0000000000000000(0000) GS:ffff8880d665f000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f44aa04f156 CR3: 00000000364d5000 CR4: 0000000000352ef0
> > Call Trace:
> >  <TASK>
> >  vma_lookup include/linux/mm.h:4204 [inline]
> >  __in_uprobe_trampoline arch/x86/kernel/uprobes.c:766 [inline]
> >  __is_optimized arch/x86/kernel/uprobes.c:1056 [inline]
> >  is_optimized arch/x86/kernel/uprobes.c:1067 [inline]
> >  set_orig_insn+0x1ec/0x2a0 arch/x86/kernel/uprobes.c:1098
> >  remove_breakpoint kernel/events/uprobes.c:1185 [inline]
> >  register_for_each_vma+0xbb7/0xdb0 kernel/events/uprobes.c:1318
> >  uprobe_unregister_nosync+0x12a/0x1c0 kernel/events/uprobes.c:1343
> >  bpf_uprobe_unregister kernel/trace/bpf_trace.c:2936 [inline]
> >  bpf_uprobe_multi_link_release+0xb3/0x1c0 kernel/trace/bpf_trace.c:2947
> >  bpf_link_free+0xec/0x4a0 kernel/bpf/syscall.c:3273
> >  bpf_link_put_direct kernel/bpf/syscall.c:3326 [inline]
> >  bpf_link_release+0x5d/0x80 kernel/bpf/syscall.c:3333
> >  __fput+0x3ff/0xb50 fs/file_table.c:512
> >  task_work_run+0x150/0x240 kernel/task_work.c:233
> >  exit_task_work include/linux/task_work.h:40 [inline]
> 
> current->mm is already NULL, the exiting task has already passed exit_mm().
> 
> Hopefully
> 
> 	[PATCHv4 01/13] uprobes/x86: Use proper mm_struct in __in_uprobe_trampoline
> 	https://lore.kernel.org/all/20260526205840.173790-2-jolsa@kernel.org/
> 
> should help...

yes, that sould fix it

thanks,
jirka