* [syzbot] [bluetooth?] general protection fault in h4_recv
@ 2026-04-09 7:42 syzbot
2026-04-09 11:21 ` Edward Adam Davis
2026-04-09 11:29 ` Edward Adam Davis
0 siblings, 2 replies; 5+ messages in thread
From: syzbot @ 2026-04-09 7:42 UTC (permalink / raw)
To: linux-bluetooth, linux-kernel, luiz.dentz, marcel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 3aae9383f42f Merge tag 'input-for-v7.0-rc6' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17814e06580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e
dashboard link: https://syzkaller.appspot.com/bug?extid=ff30eeab8e07b37d524e
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=108c0bd6580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11015d02580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46384525f287/disk-3aae9383.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bcd9d5c20ab7/vmlinux-3aae9383.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e4353e5e60e2/bzImage-3aae9383.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ff30eeab8e07b37d524e@syzkaller.appspotmail.com
RBP: 00007ffeca659d70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd7d4415fac R14: 00007fd7d4415fa0 R15: 00007fd7d4415fa0
</TASK>
Bluetooth: Can't register HCI device
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5964 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:h4_recv+0x52/0x1c0 drivers/bluetooth/hci_h4.c:112
Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 3c 01 00 00 4c 8b a3 b8 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 31 01 00 00 49 8b 34 24 48 89 ea 41 b9 04 00 00
RSP: 0018:ffffc900037afca8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888033b48400 RCX: ffffffff887767b0
RDX: 0000000000000000 RSI: ffffffff8877b6a8 RDI: ffff888033b485b8
RBP: ffffc900037afd68 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffff888033b484c0 R15: ffffffff8cc1b1c0
FS: 000055556677d500(0000) GS:ffff888124339000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7d4072140 CR3: 00000000747cb000 CR4: 00000000003526f0
Call Trace:
<TASK>
hci_uart_tty_receive+0x259/0x7e0 drivers/bluetooth/hci_ldisc.c:627
tiocsti drivers/tty/tty_io.c:2290 [inline]
tty_ioctl+0x909/0x1690 drivers/tty/tty_io.c:2706
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7d419c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeca659d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd7d4415fa0 RCX: 00007fd7d419c819
RDX: 0000200000000100 RSI: 0000000000005412 RDI: 0000000000000003
RBP: 00007fd7d4232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd7d4415fac R14: 00007fd7d4415fa0 R15: 00007fd7d4415fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:h4_recv+0x52/0x1c0 drivers/bluetooth/hci_h4.c:112
Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 3c 01 00 00 4c 8b a3 b8 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 31 01 00 00 49 8b 34 24 48 89 ea 41 b9 04 00 00
RSP: 0018:ffffc900037afca8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888033b48400 RCX: ffffffff887767b0
RDX: 0000000000000000 RSI: ffffffff8877b6a8 RDI: ffff888033b485b8
RBP: ffffc900037afd68 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffff888033b484c0 R15: ffffffff8cc1b1c0
FS: 000055556677d500(0000) GS:ffff888124339000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7d4072140 CR3: 00000000747cb000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: df 48 89 fisttps -0x77(%rax)
3: fa cli
4: 48 c1 ea 03 shr $0x3,%rdx
8: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
c: 0f 85 3c 01 00 00 jne 0x14e
12: 4c 8b a3 b8 01 00 00 mov 0x1b8(%rbx),%r12
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 4c 89 e2 mov %r12,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 31 01 00 00 jne 0x165
34: 49 8b 34 24 mov (%r12),%rsi
38: 48 89 ea mov %rbp,%rdx
3b: 41 rex.B
3c: b9 .byte 0xb9
3d: 04 00 add $0x0,%al
---
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [bluetooth?] general protection fault in h4_recv
2026-04-09 7:42 [syzbot] [bluetooth?] general protection fault in h4_recv syzbot
@ 2026-04-09 11:21 ` Edward Adam Davis
2026-04-09 12:00 ` syzbot
2026-04-09 11:29 ` Edward Adam Davis
1 sibling, 1 reply; 5+ messages in thread
From: Edward Adam Davis @ 2026-04-09 11:21 UTC (permalink / raw)
To: syzbot+ff30eeab8e07b37d524e; +Cc: linux-kernel, syzkaller-bugs
#syz test
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 71c1997a0f73..80a5b9eee123 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -615,8 +615,7 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
percpu_down_read(&hu->proto_lock);
- if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
- !test_bit(HCI_UART_PROTO_INIT, &hu->flags)) {
+ if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
percpu_up_read(&hu->proto_lock);
return;
}
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [syzbot] [bluetooth?] general protection fault in h4_recv
2026-04-09 7:42 [syzbot] [bluetooth?] general protection fault in h4_recv syzbot
2026-04-09 11:21 ` Edward Adam Davis
@ 2026-04-09 11:29 ` Edward Adam Davis
2026-04-09 12:12 ` syzbot
1 sibling, 1 reply; 5+ messages in thread
From: Edward Adam Davis @ 2026-04-09 11:29 UTC (permalink / raw)
To: syzbot+ff30eeab8e07b37d524e; +Cc: linux-kernel, syzkaller-bugs
#syz test
diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c
index a889a66a326f..07cc2a79a77b 100644
--- a/drivers/bluetooth/hci_h4.c
+++ b/drivers/bluetooth/hci_h4.c
@@ -109,6 +109,9 @@ static int h4_recv(struct hci_uart *hu, const void *data, int count)
{
struct h4_struct *h4 = hu->priv;
+ if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
+ return -EUNATCH;
+
h4->rx_skb = h4_recv_buf(hu, h4->rx_skb, data, count,
h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts));
if (IS_ERR(h4->rx_skb)) {
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-04-09 12:12 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2026-04-09 7:42 [syzbot] [bluetooth?] general protection fault in h4_recv syzbot
2026-04-09 11:21 ` Edward Adam Davis
2026-04-09 12:00 ` syzbot
2026-04-09 11:29 ` Edward Adam Davis
2026-04-09 12:12 ` syzbot
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