[syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    2d5404caa8c7 Linux 6.12-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1357fe30580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dcca673786a14715
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a2910755fac8/disk-2d5404ca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a135257837ee/vmlinux-2d5404ca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3f8930906164/bzImage-2d5404ca.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in hci_cmd_complete_evt+0xd7b/0xeb0 net/bluetooth/hci_event.c:4221
 hci_cmd_complete_evt+0xd7b/0xeb0 net/bluetooth/hci_event.c:4221
 hci_event_func net/bluetooth/hci_event.c:7440 [inline]
 hci_event_packet+0x11df/0x1c20 net/bluetooth/hci_event.c:7495
 hci_rx_work+0x9d1/0x11f0 net/bluetooth/hci_core.c:4031
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 hci_cmd_complete_evt+0xaf4/0xeb0
 hci_event_func net/bluetooth/hci_event.c:7440 [inline]
 hci_event_packet+0x11df/0x1c20 net/bluetooth/hci_event.c:7495
 hci_rx_work+0x9d1/0x11f0 net/bluetooth/hci_core.c:4031
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4091 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1322 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:494 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:487 [inline]
 vhci_write+0x127/0x900 drivers/bluetooth/hci_vhci.c:607
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xb2b/0x1540 fs/read_write.c:683
 ksys_write+0x24f/0x4c0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:748 [inline]
 __se_sys_write fs/read_write.c:745 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:745
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5791 Comm: kworker/u9:2 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: hci1 hci_rx_work
=====================================================


---
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#syz undup

Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d082ecbc71e9 Linux 6.14-rc4
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13492db0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d66f6f82ee090382
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122c37f8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10023fdf980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a9f22e75faf0/disk-d082ecbc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/336a72a11410/vmlinux-d082ecbc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7180e4935c41/bzImage-d082ecbc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in hci_cmd_complete_evt+0xd7b/0xeb0 net/bluetooth/hci_event.c:4226
 hci_cmd_complete_evt+0xd7b/0xeb0 net/bluetooth/hci_event.c:4226
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x11c8/0x1ca0 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x699/0x1260 net/bluetooth/hci_core.c:4015
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xc1a/0x1e80 kernel/workqueue.c:3317
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3398
 kthread+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 hci_cmd_complete_evt+0xaf4/0xeb0
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x11c8/0x1ca0 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x699/0x1260 net/bluetooth/hci_core.c:4015
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xc1a/0x1e80 kernel/workqueue.c:3317
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3398
 kthread+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4121 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_node_noprof+0x907/0xe00 mm/slub.c:4216
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:515
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:606
 alloc_skb include/linux/skbuff.h:1331 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:495 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:487 [inline]
 vhci_write+0x127/0x900 drivers/bluetooth/hci_vhci.c:607
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:679
 ksys_write+0x240/0x4b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:739
 x64_sys_call+0x3161/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5777 Comm: kworker/u9:2 Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: hci0 hci_rx_work
=====================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Forwarded: Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt
Author: ipravdin.official@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
	Ivan Pravdin

Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in hci_cmd_complete_evt

=====================================================
BUG: KMSAN: uninit-value in hci_cmd_complete_evt+0xca3/0xe90 net/bluetooth/hci_event.c:4210
 hci_cmd_complete_evt+0xca3/0xe90 net/bluetooth/hci_event.c:4210
 hci_event_func net/bluetooth/hci_event.c:7515 [inline]
 hci_event_packet+0xce2/0x1e40 net/bluetooth/hci_event.c:7572
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4068
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 hci_cmd_complete_evt+0xc9c/0xe90 net/bluetooth/hci_event.c:4210
 hci_event_func net/bluetooth/hci_event.c:7515 [inline]
 hci_event_packet+0xce2/0x1e40 net/bluetooth/hci_event.c:7572
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4068
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 hci_cmd_complete_evt+0x775/0xe90 net/bluetooth/hci_event.c:-1
 hci_event_func net/bluetooth/hci_event.c:7515 [inline]
 hci_event_packet+0xce2/0x1e40 net/bluetooth/hci_event.c:7572
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4068
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4153 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4248
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:578
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:669
 alloc_skb include/linux/skbuff.h:1337 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:509 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:488 [inline]
 vhci_write+0x125/0x960 drivers/bluetooth/hci_vhci.c:608
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb34/0x1560 fs/read_write.c:684
 ksys_write fs/read_write.c:736 [inline]
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:744
 x64_sys_call+0x38c3/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 53 Comm: kworker/u9:0 Not tainted 6.15.0-rc6-syzkaller-01366-g0ba714749722 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci0 hci_rx_work
=====================================================


Tested on:

commit:         0ba71474 Bluetooth: hci_event: Mask data status from L..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=13122f22580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=38456bfd5c806d6d
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

Note: no patches were applied.

Forwarded: KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: KMSAN: uninit-value in hci_cmd_complete_evt
Author: chelsyratnawat2001@gmail.com

#syz test

Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in hci_cmd_complete_evt

=====================================================
BUG: KMSAN: uninit-value in hci_cmd_complete_evt+0xca3/0xe90 net/bluetooth/hci_event.c:4226
 hci_cmd_complete_evt+0xca3/0xe90 net/bluetooth/hci_event.c:4226
 hci_event_func net/bluetooth/hci_event.c:7566 [inline]
 hci_event_packet+0xcdf/0x1e40 net/bluetooth/hci_event.c:7623
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4071
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3346
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3427
 kthread+0xd5c/0xf00 kernel/kthread.c:463
 ret_from_fork+0x233/0x380 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 hci_cmd_complete_evt+0xc9c/0xe90 net/bluetooth/hci_event.c:4226
 hci_event_func net/bluetooth/hci_event.c:7566 [inline]
 hci_event_packet+0xcdf/0x1e40 net/bluetooth/hci_event.c:7623
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4071
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3346
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3427
 kthread+0xd5c/0xf00 kernel/kthread.c:463
 ret_from_fork+0x233/0x380 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 hci_cmd_complete_evt+0x775/0xe90 net/bluetooth/hci_event.c:-1
 hci_event_func net/bluetooth/hci_event.c:7566 [inline]
 hci_event_packet+0xcdf/0x1e40 net/bluetooth/hci_event.c:7623
 hci_rx_work+0x9a8/0x12b0 net/bluetooth/hci_core.c:4071
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3346
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3427
 kthread+0xd5c/0xf00 kernel/kthread.c:463
 ret_from_fork+0x233/0x380 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4197 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4292
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:578
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:669
 alloc_skb include/linux/skbuff.h:1336 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:509 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:496 [inline]
 vhci_write+0x129/0x980 drivers/bluetooth/hci_vhci.c:617
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x3014/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5862 Comm: kworker/u9:2 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: hci0 hci_rx_work
=====================================================


Tested on:

commit:         7f707257 Merge tag 'kbuild-6.18-1' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10c065cd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=40e84ec1e5456fca
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=117fa5cd980000

Forwarded: test fix

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: test fix
Author: rpthibeault@gmail.com

#syz test

Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com
Tested-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com

Tested on:

commit:         552c5071 Merge tag 'vfio-v6.18-rc3' of https://github...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b5d734580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ed2b1ae1fa9a0fdc
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16f98614580000

Note: testing is done by a robot and is best-effort only.

Forwarded: test fix

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: test fix
Author: rpthibeault@gmail.com

#syz test

Re: [syzbot] [bluetooth?] KMSAN: uninit-value in hci_cmd_complete_evt

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com
Tested-by: syzbot+a9a4bedfca6aa9d7fa24@syzkaller.appspotmail.com

Tested on:

commit:         6fab32bb MAINTAINERS: add Mark Brown as a linux-next m..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17292d2f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ed2b1ae1fa9a0fdc
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a4bedfca6aa9d7fa24
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15957734580000

Note: testing is done by a robot and is best-effort only.