* [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields
@ 2026-05-30 20:57 syzbot
2026-05-30 23:18 ` Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered syzbot
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: syzbot @ 2026-05-30 20:57 UTC (permalink / raw)
To: linux-bluetooth, linux-kernel, luiz.dentz, marcel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: f377d0025eb0 Merge tag 'sh-for-v7.1-tag2' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1737bb48580000
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
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164ed748580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e6576c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5d8163677f58/disk-f377d002.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cf2fcdb8200b/vmlinux-f377d002.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e9fb70799318/bzImage-f377d002.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
BUG: memory leak
unreferenced object 0xffff888111f49600 (size 512):
comm "syz.0.17", pid 5937, jiffies 4294945495
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 6e7d3fde):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__kmalloc_cache_noprof+0x371/0x480 mm/slub.c:5414
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
init_srcu_struct_fields+0x2c0/0x350 kernel/rcu/srcutree.c:207
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
tty_ioctl+0xaca/0xd60 drivers/tty/tty_io.c:2801
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+0xf4/0x140 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object (percpu) 0x607e4d93d800 (size 384):
comm "syz.0.17", pid 5937, jiffies 4294945495
hex dump (first 32 bytes on cpu 0):
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 593bdea7):
pcpu_alloc_noprof+0x7c7/0xed0 mm/percpu.c:1896
init_srcu_struct_fields+0x2eb/0x350 kernel/rcu/srcutree.c:224
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
tty_ioctl+0xaca/0xd60 drivers/tty/tty_io.c:2801
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+0xf4/0x140 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object (percpu) 0x607e4d93d980 (size 384):
comm "syz.0.18", pid 5940, jiffies 4294945497
hex dump (first 32 bytes on cpu 0):
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 593bdea7):
pcpu_alloc_noprof+0x7c7/0xed0 mm/percpu.c:1896
init_srcu_struct_fields+0x2eb/0x350 kernel/rcu/srcutree.c:224
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
tty_ioctl+0xaca/0xd60 drivers/tty/tty_io.c:2801
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+0xf4/0x140 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff88811d010a00 (size 512):
comm "syz.0.19", pid 5951, jiffies 4294945502
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 2d3d1dd8):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__kmalloc_cache_noprof+0x371/0x480 mm/slub.c:5414
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
init_srcu_struct_fields+0x2c0/0x350 kernel/rcu/srcutree.c:207
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
tty_ioctl+0xaca/0xd60 drivers/tty/tty_io.c:2801
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+0xf4/0x140 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object (percpu) 0x607e4d93db00 (size 384):
comm "syz.0.19", pid 5951, jiffies 4294945502
hex dump (first 32 bytes on cpu 0):
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 593bdea7):
pcpu_alloc_noprof+0x7c7/0xed0 mm/percpu.c:1896
init_srcu_struct_fields+0x2eb/0x350 kernel/rcu/srcutree.c:224
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
tty_ioctl+0xaca/0xd60 drivers/tty/tty_io.c:2801
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+0xf4/0x140 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
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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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
* Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
2026-05-30 20:57 [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
@ 2026-05-30 23:18 ` syzbot
2026-05-30 23:20 ` syzbot
2026-05-31 0:13 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2026-05-30 23:18 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
Author: kartikey406@gmail.com
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
hci_alloc_dev_priv() initializes hdev->srcu with init_srcu_struct(), but
the matching cleanup_srcu_struct() is only called from hci_unregister_dev().
A hci_dev that is allocated and then freed without ever being registered
leaks the SRCU internals - the node array and the per-CPU sda - even though
the hci_dev itself is freed correctly.
This is reachable from the hci_uart line discipline. h5_open() (used by the
HCI_UART_3WIRE protocol) sets HCI_UART_INIT_PENDING, so hci_uart_register_dev()
returns early without calling hci_register_dev() and HCI_UART_REGISTERED is
never set. Registration is deferred until the three-wire link is synced, which
never happens over a bare pty. When the tty is closed, hci_uart_tty_close()
finds HCI_UART_REGISTERED clear, skips hci_unregister_dev(), and calls
hci_free_dev() -> hci_release_dev() -> kfree(hdev), orphaning the SRCU
allocations.
kmemleak reports only the SRCU sub-objects, not hdev, confirming that hdev is
freed while its embedded srcu is not torn down:
init_srcu_struct_fields+0x2c0/0x350 kernel/rcu/srcutree.c:207
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
Pair the SRCU init with destruction by calling cleanup_srcu_struct() from
hci_release_dev(), so it runs on the final put_device() regardless of whether
the device was ever registered. Keep synchronize_srcu() in hci_unregister_dev()
to drain readers walking the device list before the device leaves it.
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
net/bluetooth/hci_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 28d7929dc593..2d516beedb59 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2664,7 +2664,6 @@ 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);
@@ -2737,6 +2736,8 @@ 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);
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
2026-05-30 20:57 [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-30 23:18 ` Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered syzbot
@ 2026-05-30 23:20 ` syzbot
2026-05-31 0:13 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2026-05-30 23:20 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
Author: kartikey406@gmail.com
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
hci_alloc_dev_priv() initializes hdev->srcu with init_srcu_struct(), but
the matching cleanup_srcu_struct() is only called from hci_unregister_dev().
A hci_dev that is allocated and then freed without ever being registered
leaks the SRCU internals - the node array and the per-CPU sda - even though
the hci_dev itself is freed correctly.
This is reachable from the hci_uart line discipline. h5_open() (used by the
HCI_UART_3WIRE protocol) sets HCI_UART_INIT_PENDING, so hci_uart_register_dev()
returns early without calling hci_register_dev() and HCI_UART_REGISTERED is
never set. Registration is deferred until the three-wire link is synced, which
never happens over a bare pty. When the tty is closed, hci_uart_tty_close()
finds HCI_UART_REGISTERED clear, skips hci_unregister_dev(), and calls
hci_free_dev() -> hci_release_dev() -> kfree(hdev), orphaning the SRCU
allocations.
kmemleak reports only the SRCU sub-objects, not hdev, confirming that hdev is
freed while its embedded srcu is not torn down:
init_srcu_struct_fields+0x2c0/0x350 kernel/rcu/srcutree.c:207
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
Pair the SRCU init with destruction by calling cleanup_srcu_struct() from
hci_release_dev(), so it runs on the final put_device() regardless of whether
the device was ever registered. Keep synchronize_srcu() in hci_unregister_dev()
to drain readers walking the device list before the device leaves it.
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
net/bluetooth/hci_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 28d7929dc593..2d516beedb59 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2664,7 +2664,6 @@ 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);
@@ -2737,6 +2736,8 @@ 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);
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
2026-05-30 20:57 [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-30 23:18 ` Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered syzbot
2026-05-30 23:20 ` syzbot
@ 2026-05-31 0:13 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2026-05-31 0:13 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered
Author: kartikey406@gmail.com
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
hci_alloc_dev_priv() initializes hdev->srcu with init_srcu_struct(), but
the matching cleanup_srcu_struct() is only called from hci_unregister_dev().
A hci_dev that is allocated and then freed without ever being registered
leaks the SRCU internals - the node array and the per-CPU sda - even though
the hci_dev itself is freed correctly.
This is reachable from the hci_uart line discipline. h5_open() (used by the
HCI_UART_3WIRE protocol) sets HCI_UART_INIT_PENDING, so hci_uart_register_dev()
returns early without calling hci_register_dev() and HCI_UART_REGISTERED is
never set. Registration is deferred until the three-wire link is synced, which
never happens over a bare pty. When the tty is closed, hci_uart_tty_close()
finds HCI_UART_REGISTERED clear, skips hci_unregister_dev(), and calls
hci_free_dev() -> hci_release_dev() -> kfree(hdev), orphaning the SRCU
allocations.
kmemleak reports only the SRCU sub-objects, not hdev, confirming that hdev is
freed while its embedded srcu is not torn down:
init_srcu_struct_fields+0x2c0/0x350 kernel/rcu/srcutree.c:207
hci_alloc_dev_priv+0x37/0x680 net/bluetooth/hci_core.c:2453
hci_alloc_dev include/net/bluetooth/hci_core.h:1763 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:644 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:720 [inline]
hci_uart_tty_ioctl+0x173/0x460 drivers/bluetooth/hci_ldisc.c:774
Pair the SRCU init with destruction by calling cleanup_srcu_struct() from
hci_release_dev(), so it runs on the final put_device() regardless of whether
the device was ever registered. Keep synchronize_srcu() in hci_unregister_dev()
to drain readers walking the device list before the device leaves it.
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
net/bluetooth/hci_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 28d7929dc593..2d516beedb59 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2664,7 +2664,6 @@ 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);
@@ -2737,6 +2736,8 @@ 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);
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-05-31 0:13 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-30 20:57 [syzbot] [bluetooth?] memory leak in init_srcu_struct_fields syzbot
2026-05-30 23:18 ` Forwarded: [PATCH] Bluetooth: hci_core: Fix SRCU leak when device is freed unregistered syzbot
2026-05-30 23:20 ` syzbot
2026-05-31 0:13 ` syzbot
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