* [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev()
2026-05-31 1:19 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
@ 2026-05-31 14:25 ` Bharath Reddy
2026-05-31 14:59 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-31 14:41 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
2026-05-31 15:27 ` [PATCH v2] Bluetooth: fix memory leak in error path of hci_alloc_dev() Bharath Reddy
2 siblings, 1 reply; 7+ messages in thread
From: Bharath Reddy @ 2026-05-31 14:25 UTC (permalink / raw)
To: syzbot+535ecc844591e50588a5
Cc: kartikey406, linux-kernel, syzkaller-bugs, Bharath Reddy
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
Syzbot caught a percpu memory leak in the SRCU struct when Bluetooth
HCI UART configuration fails early.
The problem boils down to a bypassed destructor. If device setup fails
before hci_register_dev() completes, the HCI_UNREGISTER flag is never
set. Later, when the device is freed, bt_host_release() sees this flag
is missing, skips hci_release_dev(), and jumps straight to kfree(hdev).
This leaks the SRCU memory, which was also incorrectly being cleaned up
in hci_unregister_dev() which is also skipped during an early abort.
To fix this and properly balance the allocation and teardown paths:
1. Move cleanup_srcu_struct() into hci_release_dev() so it directly
mirrors the allocation in hci_alloc_dev().
2. Unconditionally call hci_release_dev() from bt_host_release() by
dropping the HCI_UNREGISTER check. This is safe for unregistered
devices since it only cleans up resources initialized early on in
hci_alloc_dev().
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Signed-off-by: Bharath Reddy <kbreddy.rpbc@gmail.com>
---
net/bluetooth/hci_core.c | 3 ++-
net/bluetooth/hci_sysfs.c | 6 ++----
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index c46c1236ebfa..f6bc7cb3e55c 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2701,7 +2701,6 @@ void hci_unregister_dev(struct hci_dev *hdev)
write_unlock(&hci_dev_list_lock);
synchronize_srcu(&hdev->srcu);
- cleanup_srcu_struct(&hdev->srcu);
disable_work_sync(&hdev->rx_work);
disable_work_sync(&hdev->cmd_work);
@@ -2774,6 +2773,8 @@ void hci_release_dev(struct hci_dev *hdev)
kfree_skb(hdev->sent_cmd);
kfree_skb(hdev->req_skb);
kfree_skb(hdev->recv_event);
+
+ cleanup_srcu_struct(&hdev->srcu);
kfree(hdev);
}
EXPORT_SYMBOL(hci_release_dev);
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 041ce9adc378..261b28a25b02 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -83,10 +83,8 @@ static void bt_host_release(struct device *dev)
{
struct hci_dev *hdev = to_hci_dev(dev);
- if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
- hci_release_dev(hdev);
- else
- kfree(hdev);
+ hci_release_dev(hdev);
+
module_put(THIS_MODULE);
}
--
2.34.1
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields
2026-05-31 14:25 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
@ 2026-05-31 14:59 ` syzbot
0 siblings, 0 replies; 7+ messages in thread
From: syzbot @ 2026-05-31 14:59 UTC (permalink / raw)
To: kartikey406, kbreddy.rpbc, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel NULL pointer dereference in hci_release_dev
BUG: kernel NULL pointer dereference, address: 00000000000000b0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 800000011280f067 P4D 800000011280f067 PUD 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 1 UID: 0 PID: 6587 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:workqueue_sysfs_unregister kernel/workqueue.c:7632 [inline]
RIP: 0010:destroy_workqueue+0x1a/0x430 kernel/workqueue.c:6045
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 66 d6 15 00 <49> 8b 9d b0 00 00 00 48 85 db 74 19 e8 55 d6 15 00 48 8d 7b 08 49
RSP: 0018:ffffc90002177c68 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88811cb86000 RCX: ffffffff81a2820c
RDX: ffff88810aac91c0 RSI: ffffffff816e808a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000000
R10: ffffffff85600000 R11: 0000000000000001 R12: ffff88811cb87390
R13: 0000000000000000 R14: ffff88811cb86030 R15: 0000000000000000
FS: 000055556c326500(0000) GS:ffff8881b23e5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000b0 CR3: 0000000129ede000 CR4: 00000000003526f0
Call Trace:
<TASK>
hci_release_dev+0x62/0x250 net/bluetooth/hci_core.c:2712
bt_host_release+0x19/0x30 net/bluetooth/hci_sysfs.c:86
device_release+0x4d/0xd0 drivers/base/core.c:2566
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0xe4/0x1d0 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3814
hci_uart_tty_close+0x155/0x1a0 drivers/bluetooth/hci_ldisc.c:587
tty_ldisc_close+0x51/0x70 drivers/tty/tty_ldisc.c:455
tty_ldisc_kill drivers/tty/tty_ldisc.c:613 [inline]
tty_ldisc_release+0xd5/0x2d0 drivers/tty/tty_ldisc.c:781
tty_release_struct+0x1a/0x90 drivers/tty/tty_io.c:1681
tty_release+0x6b0/0x6c0 drivers/tty/tty_io.c:1852
__fput+0x1b5/0x500 fs/file_table.c:510
task_work_run+0x95/0xf0 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xd9/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x485/0x600 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe03af9cdd9
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:00007ffeee0ab038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffeee0ab120 RCX: 00007fe03af9cdd9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001bd43 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31220000 R11: 0000000000000246 R12: 00007ffeee0ab160
R13: 00007fe03b215fac R14: 000000000001bd76 R15: 00007fe03b215fa0
</TASK>
Modules linked in:
CR2: 00000000000000b0
---[ end trace 0000000000000000 ]---
RIP: 0010:workqueue_sysfs_unregister kernel/workqueue.c:7632 [inline]
RIP: 0010:destroy_workqueue+0x1a/0x430 kernel/workqueue.c:6045
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 66 d6 15 00 <49> 8b 9d b0 00 00 00 48 85 db 74 19 e8 55 d6 15 00 48 8d 7b 08 49
RSP: 0018:ffffc90002177c68 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88811cb86000 RCX: ffffffff81a2820c
RDX: ffff88810aac91c0 RSI: ffffffff816e808a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000000
R10: ffffffff85600000 R11: 0000000000000001 R12: ffff88811cb87390
R13: 0000000000000000 R14: ffff88811cb86030 R15: 0000000000000000
FS: 000055556c326500(0000) GS:ffff8881b23e5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000b0 CR3: 0000000129ede000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: f3 0f 1e fa endbr64
14: 41 57 push %r15
16: 41 56 push %r14
18: 41 55 push %r13
1a: 49 89 fd mov %rdi,%r13
1d: 41 54 push %r12
1f: 55 push %rbp
20: 53 push %rbx
21: 48 83 ec 08 sub $0x8,%rsp
25: e8 66 d6 15 00 call 0x15d690
* 2a: 49 8b 9d b0 00 00 00 mov 0xb0(%r13),%rbx <-- trapping instruction
31: 48 85 db test %rbx,%rbx
34: 74 19 je 0x4f
36: e8 55 d6 15 00 call 0x15d690
3b: 48 8d 7b 08 lea 0x8(%rbx),%rdi
3f: 49 rex.WB
Tested on:
commit: 174914ea Merge tag 'v7.1-rc6-smb3-client-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17cb69a6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5733044df9370cfc
dashboard link: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=114b7ed2580000
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev()
2026-05-31 1:19 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-31 14:25 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
@ 2026-05-31 14:41 ` Bharath Reddy
2026-05-31 15:27 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-31 15:27 ` [PATCH v2] Bluetooth: fix memory leak in error path of hci_alloc_dev() Bharath Reddy
2 siblings, 1 reply; 7+ messages in thread
From: Bharath Reddy @ 2026-05-31 14:41 UTC (permalink / raw)
To: syzbot+535ecc844591e50588a5
Cc: kartikey406, linux-kernel, syzkaller-bugs, Bharath Reddy
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f377d0025eb0
Syzbot caught a percpu memory leak in the SRCU struct when Bluetooth
HCI UART configuration fails early.
The problem boils down to a bypassed destructor. If device setup fails
before hci_register_dev() completes, the HCI_UNREGISTER flag is never
set. Later, when the device is freed, bt_host_release() sees this flag
is missing, skips hci_release_dev(), and jumps straight to kfree(hdev).
This leaks the SRCU memory, which was also incorrectly being cleaned up
in hci_unregister_dev() which is also skipped during an early abort.
To fix this and properly balance the allocation and teardown paths:
1. Move cleanup_srcu_struct() into hci_release_dev() so it directly
mirrors the allocation in hci_alloc_dev().
2. Unconditionally call hci_release_dev() from bt_host_release() by
dropping the HCI_UNREGISTER check. This is safe for unregistered
devices since it only cleans up resources initialized early on in
hci_alloc_dev().
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Signed-off-by: Bharath Reddy <kbreddy.rpbc@gmail.com>
---
net/bluetooth/hci_core.c | 3 ++-
net/bluetooth/hci_sysfs.c | 6 ++----
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index c46c1236ebfa..f6bc7cb3e55c 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2701,7 +2701,6 @@ void hci_unregister_dev(struct hci_dev *hdev)
write_unlock(&hci_dev_list_lock);
synchronize_srcu(&hdev->srcu);
- cleanup_srcu_struct(&hdev->srcu);
disable_work_sync(&hdev->rx_work);
disable_work_sync(&hdev->cmd_work);
@@ -2774,6 +2773,8 @@ void hci_release_dev(struct hci_dev *hdev)
kfree_skb(hdev->sent_cmd);
kfree_skb(hdev->req_skb);
kfree_skb(hdev->recv_event);
+
+ cleanup_srcu_struct(&hdev->srcu);
kfree(hdev);
}
EXPORT_SYMBOL(hci_release_dev);
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 041ce9adc378..261b28a25b02 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -83,10 +83,8 @@ static void bt_host_release(struct device *dev)
{
struct hci_dev *hdev = to_hci_dev(dev);
- if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
- hci_release_dev(hdev);
- else
- kfree(hdev);
+ hci_release_dev(hdev);
+
module_put(THIS_MODULE);
}
--
2.34.1
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields
2026-05-31 14:41 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
@ 2026-05-31 15:27 ` syzbot
0 siblings, 0 replies; 7+ messages in thread
From: syzbot @ 2026-05-31 15:27 UTC (permalink / raw)
To: kartikey406, kbreddy.rpbc, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel NULL pointer dereference in hci_release_dev
BUG: kernel NULL pointer dereference, address: 00000000000000b0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 800000012a7b5067 P4D 800000012a7b5067 PUD 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 1 UID: 0 PID: 6583 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:workqueue_sysfs_unregister kernel/workqueue.c:7607 [inline]
RIP: 0010:destroy_workqueue+0x1a/0x430 kernel/workqueue.c:6020
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 06 d2 15 00 <49> 8b 9d b0 00 00 00 48 85 db 74 19 e8 f5 d1 15 00 48 8d 7b 08 49
RSP: 0018:ffffc90002aafc78 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8881141e0000 RCX: ffffffff81a266cc
RDX: ffff88810a6311c0 RSI: ffffffff816e6f0a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000000
R10: ffffffff85600000 R11: 0000000000000001 R12: ffff8881141e1390
R13: 0000000000000000 R14: ffff8881141e0030 R15: 0000000000000000
FS: 000055559230a500(0000) GS:ffff8881b23ec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000b0 CR3: 000000012983e000 CR4: 00000000003526f0
Call Trace:
<TASK>
hci_release_dev+0x62/0x250 net/bluetooth/hci_core.c:2749
bt_host_release+0x19/0x30 net/bluetooth/hci_sysfs.c:86
device_release+0x4d/0xd0 drivers/base/core.c:2566
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0xe4/0x1d0 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3814
hci_uart_tty_close+0xf7/0x120 drivers/bluetooth/hci_ldisc.c:558
tty_ldisc_close+0x51/0x70 drivers/tty/tty_ldisc.c:455
tty_ldisc_kill drivers/tty/tty_ldisc.c:613 [inline]
tty_ldisc_release+0xd5/0x2d0 drivers/tty/tty_ldisc.c:781
tty_release_struct+0x1a/0x90 drivers/tty/tty_io.c:1681
tty_release+0x6b0/0x6c0 drivers/tty/tty_io.c:1852
__fput+0x1b5/0x500 fs/file_table.c:510
task_work_run+0x95/0xf0 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xcf/0x440 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x485/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57d6b9cdd9
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:00007fff37ccc228 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fff37ccc310 RCX: 00007f57d6b9cdd9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001baba R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31820000 R11: 0000000000000246 R12: 00007fff37ccc350
R13: 00007f57d6e15fac R14: 000000000001baed R15: 00007f57d6e15fa0
</TASK>
Modules linked in:
CR2: 00000000000000b0
---[ end trace 0000000000000000 ]---
RIP: 0010:workqueue_sysfs_unregister kernel/workqueue.c:7607 [inline]
RIP: 0010:destroy_workqueue+0x1a/0x430 kernel/workqueue.c:6020
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 06 d2 15 00 <49> 8b 9d b0 00 00 00 48 85 db 74 19 e8 f5 d1 15 00 48 8d 7b 08 49
RSP: 0018:ffffc90002aafc78 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8881141e0000 RCX: ffffffff81a266cc
RDX: ffff88810a6311c0 RSI: ffffffff816e6f0a RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000000
R10: ffffffff85600000 R11: 0000000000000001 R12: ffff8881141e1390
R13: 0000000000000000 R14: ffff8881141e0030 R15: 0000000000000000
FS: 000055559230a500(0000) GS:ffff8881b23ec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000b0 CR3: 000000012983e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: f3 0f 1e fa endbr64
14: 41 57 push %r15
16: 41 56 push %r14
18: 41 55 push %r13
1a: 49 89 fd mov %rdi,%r13
1d: 41 54 push %r12
1f: 55 push %rbp
20: 53 push %rbx
21: 48 83 ec 08 sub $0x8,%rsp
25: e8 06 d2 15 00 call 0x15d230
* 2a: 49 8b 9d b0 00 00 00 mov 0xb0(%r13),%rbx <-- trapping instruction
31: 48 85 db test %rbx,%rbx
34: 74 19 je 0x4f
36: e8 f5 d1 15 00 call 0x15d230
3b: 48 8d 7b 08 lea 0x8(%rbx),%rdi
3f: 49 rex.WB
Tested on:
commit: f377d002 Merge tag 'sh-for-v7.1-tag2' of git://git.ker..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=14789d7e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9645c21cfd1d3e8f
dashboard link: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=10392ab6580000
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2] Bluetooth: fix memory leak in error path of hci_alloc_dev()
2026-05-31 1:19 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-31 14:25 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
2026-05-31 14:41 ` [PATCH] Bluetooth: fix memory leaks in error path of hci_alloc_dev() Bharath Reddy
@ 2026-05-31 15:27 ` Bharath Reddy
2026-05-31 16:11 ` [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2 siblings, 1 reply; 7+ messages in thread
From: Bharath Reddy @ 2026-05-31 15:27 UTC (permalink / raw)
To: syzbot+535ecc844591e50588a5
Cc: kartikey406, linux-kernel, syzkaller-bugs, Bharath Reddy
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f377d0025eb0
Early failures in Bluetooth HCI UART configuration leak SRCU percpu
memory.
When device initialization fails before hci_register_dev() completes,
the HCI_UNREGISTER flag is never set. As a result, when the device
reference count reaches zero, bt_host_release() evaluates this flag as
false and falls back to a direct kfree(hdev).
Because hci_release_dev() is bypassed, the SRCU struct initialized
early in hci_alloc_dev() is never cleaned up, resulting in a leak of
percpu memory.
Fix the leak by explicitly calling cleanup_srcu_struct() in the
fallback (unregistered) branch of bt_host_release() before freeing
the device.
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Signed-off-by: Bharath Reddy <kbreddy.rpbc@gmail.com>
---
net/bluetooth/hci_sysfs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 041ce9adc378..74131f2c3be6 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -85,8 +85,10 @@ static void bt_host_release(struct device *dev)
if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
hci_release_dev(hdev);
- else
+ else {
+ cleanup_srcu_struct(&hdev->srcu);
kfree(hdev);
+ }
module_put(THIS_MODULE);
}
--
2.34.1
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