* [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk
@ 2025-11-17 14:24 syzbot
2025-11-19 2:46 ` shaurya
2025-11-19 18:45 ` shaurya
0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2025-11-17 14:24 UTC (permalink / raw)
To: johan.hedberg, linux-bluetooth, linux-kernel, linux-usb,
luiz.dentz, marcel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: e927c520e1ba Merge tag 'loongarch-fixes-6.18-1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10158d32580000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb128cd5cb439809
dashboard link: https://syzkaller.appspot.com/bug?extid=f098d64cc684b8dbaf65
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1782c914580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10a5f0b4580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b755c257d71b/disk-e927c520.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b906cb4856d7/vmlinux-e927c520.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bb3525aba146/bzImage-e927c520.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f098d64cc684b8dbaf65@syzkaller.appspotmail.com
BUG: memory leak
unreferenced object 0xffff888112c22900 (size 240):
comm "kworker/u9:1", pid 5133, jiffies 4294947154
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 6c5ee80a):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
__alloc_skb+0x203/0x240 net/core/skbuff.c:660
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:250
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:332
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff88810b0ee3c0 (size 704):
comm "kworker/u9:1", pid 5133, jiffies 4294947154
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 4e765d9f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
kmalloc_reserve+0xe6/0x180 net/core/skbuff.c:579
__alloc_skb+0xd4/0x240 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:250
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:332
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff888112c22b00 (size 240):
comm "kworker/u9:1", pid 5133, jiffies 4294947360
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc a204b710):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
__alloc_skb+0x203/0x240 net/core/skbuff.c:660
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:250
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:332
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff88810b0edb80 (size 704):
comm "kworker/u9:1", pid 5133, jiffies 4294947360
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 4e765d9f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
kmalloc_reserve+0xe6/0x180 net/core/skbuff.c:579
__alloc_skb+0xd4/0x240 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:250
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:332
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
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.
If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk
2025-11-17 14:24 [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk syzbot
@ 2025-11-19 2:46 ` shaurya
2025-11-19 18:45 ` shaurya
1 sibling, 0 replies; 4+ messages in thread
From: shaurya @ 2025-11-19 2:46 UTC (permalink / raw)
To: syzbot+f098d64cc684b8dbaf65
Cc: linux-bluetooth, linux-kernel, linux-usb, syzkaller-bugs
[-- Attachment #1: Type: text/html, Size: 240 bytes --]
[-- Attachment #2: 0001-Bluetooth-hci_sync-fix-memory-leak-in-__hci_cmd_sync.patch --]
[-- Type: text/x-patch, Size: 2002 bytes --]
From da73ec851aa5ec19b429c4cf8b9e2cd6a42e6e1e Mon Sep 17 00:00:00 2001
From: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
Date: Wed, 19 Nov 2025 08:01:33 +0530
Subject: [PATCH] Bluetooth: hci_sync: fix memory leak in __hci_cmd_sync_sk
Fix a memory leak in __hci_cmd_sync_sk where allocated request command
SKBs are not properly cleaned up when the function fails.
The issue occurs when hci_cmd_sync_alloc() successfully allocates an SKB
and it gets queued via hci_cmd_sync_add(), but then __hci_cmd_sync_sk()
fails due to timeout, interruption, or cancellation. In these error
paths, the req_skb that was cloned and stored in hdev->req_skb is not
freed, leading to memory leaks.
The memory leak can be reproduced when __hci_cmd_sync_sk() allocates
and queues an HCI command SKB, and hci_req_sync_run() transfers this
SKB to hdev->cmd_q and clones it to hdev->req_skb. If the subsequent
wait_event_interruptible_timeout() call fails (due to timeout or
interruption), the function returns an error without hdev->req_skb
ever being cleaned up.
The fix ensures that when __hci_cmd_sync_sk() returns an error, any
pending request command SKB in hdev->req_skb is properly freed before
returning. This matches the cleanup pattern used elsewhere in the HCI
sync code.
Reported-by: syzbot+f098d64cc684b8dbaf65@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f098d64cc684b8dbaf65
Signed-off-by: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
---
net/bluetooth/hci_sync.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 6e76798ec786..fbaa5749ad7b 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -203,6 +203,11 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
if (err < 0) {
kfree_skb(skb);
+ /* Clean up any pending request command */
+ if (hdev->req_skb) {
+ kfree_skb(hdev->req_skb);
+ hdev->req_skb = NULL;
+ }
return ERR_PTR(err);
}
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk
2025-11-17 14:24 [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk syzbot
2025-11-19 2:46 ` shaurya
@ 2025-11-19 18:45 ` shaurya
2025-11-19 19:32 ` syzbot
1 sibling, 1 reply; 4+ messages in thread
From: shaurya @ 2025-11-19 18:45 UTC (permalink / raw)
To: syzbot+f098d64cc684b8dbaf65; +Cc: linux-bluetooth, linux-kernel, syzkaller-bugs
[-- Attachment #1: Type: text/plain, Size: 83 bytes --]
#syz test:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
[-- Attachment #2: 0001-Bluetooth-hci_sync-fix-memory-leak-in-__hci_cmd_sync.patch --]
[-- Type: text/x-patch, Size: 2002 bytes --]
From 31c93fbc37d699e498cf51f7dc17e69cb210faaf Mon Sep 17 00:00:00 2001
From: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
Date: Thu, 20 Nov 2025 00:11:40 +0530
Subject: [PATCH] Bluetooth: hci_sync: fix memory leak in __hci_cmd_sync_sk
Fix a memory leak in __hci_cmd_sync_sk where allocated request command
SKBs are not properly cleaned up when the function fails.
The issue occurs when hci_cmd_sync_alloc() successfully allocates an SKB
and it gets queued via hci_cmd_sync_add(), but then __hci_cmd_sync_sk()
fails due to timeout, interruption, or cancellation. In these error
paths, the req_skb that was cloned and stored in hdev->req_skb is not
freed, leading to memory leaks.
The memory leak can be reproduced when __hci_cmd_sync_sk() allocates
and queues an HCI command SKB, and hci_req_sync_run() transfers this
SKB to hdev->cmd_q and clones it to hdev->req_skb. If the subsequent
wait_event_interruptible_timeout() call fails (due to timeout or
interruption), the function returns an error without hdev->req_skb
ever being cleaned up.
The fix ensures that when __hci_cmd_sync_sk() returns an error, any
pending request command SKB in hdev->req_skb is properly freed before
returning. This matches the cleanup pattern used elsewhere in the HCI
sync code.
Reported-by: syzbot+f098d64cc684b8dbaf65@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f098d64cc684b8dbaf65
Signed-off-by: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
---
net/bluetooth/hci_sync.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 6e76798ec786..fbaa5749ad7b 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -203,6 +203,11 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
if (err < 0) {
kfree_skb(skb);
+ /* Clean up any pending request command */
+ if (hdev->req_skb) {
+ kfree_skb(hdev->req_skb);
+ hdev->req_skb = NULL;
+ }
return ERR_PTR(err);
}
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk
2025-11-19 18:45 ` shaurya
@ 2025-11-19 19:32 ` syzbot
0 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2025-11-19 19:32 UTC (permalink / raw)
To: linux-bluetooth, linux-kernel, ssranevjti, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
memory leak in __hci_cmd_sync_sk
2025/11/19 19:30:48 executed programs: 47
2025/11/19 19:30:56 executed programs: 49
2025/11/19 19:31:03 executed programs: 51
2025/11/19 19:31:11 executed programs: 53
BUG: memory leak
unreferenced object 0xffff888111aec700 (size 240):
comm "kworker/u9:1", pid 5135, jiffies 4294955520
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc d1edf5a3):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
__alloc_skb+0x203/0x240 net/core/skbuff.c:660
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:255
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:337
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff88810a34a680 (size 704):
comm "kworker/u9:1", pid 5135, jiffies 4294955520
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 4e765d9f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4983 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5340
kmalloc_reserve+0xe6/0x180 net/core/skbuff.c:579
__alloc_skb+0xd4/0x240 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
hci_cmd_sync_alloc+0x30/0x140 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x84/0x290 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_ev+0x3e/0x50 net/bluetooth/hci_sync.c:255
send_hci_cmd_sync+0x5e/0xf0 net/bluetooth/mgmt.c:2615
hci_cmd_sync_work+0xd5/0x160 net/bluetooth/hci_sync.c:337
process_one_work+0x26b/0x620 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x2c4/0x4f0 kernel/workqueue.c:3427
kthread+0x15b/0x310 kernel/kthread.c:463
ret_from_fork+0x210/0x240 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF
Tested on:
commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13e81a12580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f30cc590c4f6da44
dashboard link: https://syzkaller.appspot.com/bug?extid=f098d64cc684b8dbaf65
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=10d6f332580000
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-11-19 19:32 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-11-17 14:24 [syzbot] [bluetooth?] [usb?] memory leak in __hci_cmd_sync_sk syzbot
2025-11-19 2:46 ` shaurya
2025-11-19 18:45 ` shaurya
2025-11-19 19:32 ` syzbot
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