| Message ID | 1583589488-22450-1-git-send-email-hqjagain@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Marcel Holtmann |
| Headers | show |
| Series | bluetooth/rfcomm: fix ODEBUG bug in rfcomm_dev_ioctl | expand |
Hello, syzbot found the following crash on: HEAD commit: fb279f4e Merge branch 'i2c/for-current-fixed' of git://git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=168c481de00000 kernel config: https://syzkaller.appspot.com/x/.config?x=8b13b05f0e61d957 dashboard link: https://syzkaller.appspot.com/bug?extid=4496e82090657320efc6 compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com ------------[ cut here ]------------ ODEBUG: free active (active state 0) object type: timer_list hint: rfcomm_dlc_timeout+0x0/0xc0 net/bluetooth/rfcomm/core.c:300 WARNING: CPU: 0 PID: 9181 at lib/debugobjects.c:488 debug_print_object lib/debugobjects.c:485 [inline] WARNING: CPU: 0 PID: 9181 at lib/debugobjects.c:488 __debug_check_no_obj_freed lib/debugobjects.c:967 [inline] WARNING: CPU: 0 PID: 9181 at lib/debugobjects.c:488 debug_check_no_obj_freed+0x45c/0x640 lib/debugobjects.c:998 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9181 Comm: syz-executor.3 Not tainted 5.6.0-rc3-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+0x1e9/0x30e lib/dump_stack.c:118 panic+0x264/0x7a0 kernel/panic.c:221 __warn+0x209/0x210 kernel/panic.c:582 report_bug+0x1ac/0x2d0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0xca/0x1c0 arch/x86/kernel/traps.c:267 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:debug_print_object lib/debugobjects.c:485 [inline] RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:967 [inline] RIP: 0010:debug_check_no_obj_freed+0x45c/0x640 lib/debugobjects.c:998 Code: 74 08 4c 89 f7 e8 64 2d 18 fe 4d 8b 06 48 c7 c7 53 10 d1 88 48 c7 c6 0f 01 cf 88 48 89 da 89 e9 4d 89 f9 31 c0 e8 c4 cd ae fd <0f> 0b 48 ba 00 00 00 00 00 fc ff df ff 05 c6 39 b1 05 48 8b 5c 24 RSP: 0018:ffffc90001907c88 EFLAGS: 00010046 RAX: 72f8f847df918a00 RBX: ffffffff88d4edca RCX: 0000000000040000 RDX: ffffc90011373000 RSI: 0000000000013ee9 RDI: 0000000000013eea RBP: 0000000000000000 R08: ffffffff815e1276 R09: ffffed1015d04592 R10: ffffed1015d04592 R11: 0000000000000000 R12: ffff88808ea6fbac R13: ffffffff8b592e40 R14: ffffffff890ddc78 R15: ffffffff873dcc50 kfree+0xfc/0x220 mm/slab.c:3756 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline] __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0xe37/0x2340 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x79/0xa0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0x7b/0x260 net/socket.c:1053 sock_ioctl+0x4aa/0x690 net/socket.c:1204 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c4a9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd490578c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd4905796d4 RCX: 000000000045c4a9 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000317 R14: 00000000004c5443 R15: 000000000076bf2c Kernel Offset: disabled Rebooting in 86400 seconds.. Qiujun Huang <hqjagain@gmail.com> 于2020年3月7日周六 下午10:00写道： > > Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't > increase dlc->refcnt. > > Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com > Signed-off-by: Qiujun Huang <hqjagain@gmail.com> > --- > net/bluetooth/rfcomm/tty.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c > index 0c7d31c..ea2a1df0 100644 > --- a/net/bluetooth/rfcomm/tty.c > +++ b/net/bluetooth/rfcomm/tty.c > @@ -414,7 +414,6 @@ static int __rfcomm_create_dev(struct sock *sk, void __user *arg) > if (IS_ERR(dlc)) > return PTR_ERR(dlc); > else if (dlc) { > - rfcomm_dlc_put(dlc); > return -EBUSY; > } > dlc = rfcomm_dlc_alloc(GFP_KERNEL); > -- > 1.8.3.1 >
Hi Qiujun, > Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't > increase dlc->refcnt. > > Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com > Signed-off-by: Qiujun Huang <hqjagain@gmail.com> > --- > net/bluetooth/rfcomm/tty.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c > index 0c7d31c..ea2a1df0 100644 > --- a/net/bluetooth/rfcomm/tty.c > +++ b/net/bluetooth/rfcomm/tty.c > @@ -414,7 +414,6 @@ static int __rfcomm_create_dev(struct sock *sk, void __user *arg) > if (IS_ERR(dlc)) > return PTR_ERR(dlc); > else if (dlc) { > - rfcomm_dlc_put(dlc); > return -EBUSY; > } > dlc = rfcomm_dlc_alloc(GFP_KERNEL); Please see the proposed change from Hillf. It is better to not bother with the else if here since the if statement will already leave the function. if (dlc) return -EBUSY; Regards Marcel
On Sun, Mar 8, 2020 at 4:18 PM Marcel Holtmann <marcel@holtmann.org> wrote: > > Hi Qiujun, > > > Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't > > increase dlc->refcnt. > > > > Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com > > Signed-off-by: Qiujun Huang <hqjagain@gmail.com> > > --- > > net/bluetooth/rfcomm/tty.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c > > index 0c7d31c..ea2a1df0 100644 > > --- a/net/bluetooth/rfcomm/tty.c > > +++ b/net/bluetooth/rfcomm/tty.c > > @@ -414,7 +414,6 @@ static int __rfcomm_create_dev(struct sock *sk, void __user *arg) > > if (IS_ERR(dlc)) > > return PTR_ERR(dlc); > > else if (dlc) { > > - rfcomm_dlc_put(dlc); > > return -EBUSY; > > } > > dlc = rfcomm_dlc_alloc(GFP_KERNEL); > > Please see the proposed change from Hillf. > > It is better to not bother with the else if here since the if statement will already leave the function. I get that. Thanks. > > if (dlc) > return -EBUSY; > > Regards > > Marcel >
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c index 0c7d31c..ea2a1df0 100644 --- a/net/bluetooth/rfcomm/tty.c +++ b/net/bluetooth/rfcomm/tty.c @@ -414,7 +414,6 @@ static int __rfcomm_create_dev(struct sock *sk, void __user *arg) if (IS_ERR(dlc)) return PTR_ERR(dlc); else if (dlc) { - rfcomm_dlc_put(dlc); return -EBUSY; } dlc = rfcomm_dlc_alloc(GFP_KERNEL);
Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't increase dlc->refcnt. Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang <hqjagain@gmail.com> --- net/bluetooth/rfcomm/tty.c | 1 - 1 file changed, 1 deletion(-)