linux-kernel - Re: [syzbot] [lsm?] [net?] WARNING in kvfree_call

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Message-ID: <6870afa6.a00a0220.26a83e.003d.GAE@google.com>
Date: Thu, 10 Jul 2025 23:31:02 -0700
From: syzbot <syzbot+40bf00346c3fe40f90f2@...kaller.appspotmail.com>
To: hdanton@...a.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [lsm?] [net?] WARNING in kvfree_call_rcu

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in kvfree_call_rcu

------------[ cut here ]------------
ODEBUG: activate active (active state 1) object: 00000000d15d938c object type: rcu_head hint: 0x0
WARNING: CPU: 0 PID: 7470 at lib/debugobjects.c:615 debug_print_object lib/debugobjects.c:612 [inline]
WARNING: CPU: 0 PID: 7470 at lib/debugobjects.c:615 debug_object_activate+0x344/0x460 lib/debugobjects.c:842
Modules linked in:
CPU: 0 UID: 0 PID: 7470 Comm: syz.0.17 Not tainted 6.16.0-rc5-syzkaller-00067-gec4801305969-dirty #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : debug_print_object lib/debugobjects.c:612 [inline]
pc : debug_object_activate+0x344/0x460 lib/debugobjects.c:842
lr : debug_print_object lib/debugobjects.c:612 [inline]
lr : debug_object_activate+0x344/0x460 lib/debugobjects.c:842
sp : ffff80009c3b76d0
x29: ffff80009c3b76d0 x28: ffff8000976d8000 x27: dfff800000000000
x26: ffff80008afc2440 x25: 0000000000000001 x24: ffff8000891ac400
x23: 0000000000000003 x22: ffff80008b5399e0 x21: 0000000000000000
x20: ffff80008afc2440 x19: ffff8000891ac400 x18: 0000000000000000
x17: 3833396435316430 x16: ffff80008aefc458 x15: 0000000000000001
x14: 1fffe000337d40e2 x13: 0000000000000000 x12: 0000000000000000
x11: ffff6000337d40e3 x10: 0000000000ff0100 x9 : 5688875a670f5200
x8 : 5688875a670f5200 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80009c3b7018 x4 : ffff80008f766be0 x3 : ffff8000807bcfac
x2 : 0000000000000001 x1 : 0000000100000202 x0 : 0000000000000000
Call trace:
 debug_print_object lib/debugobjects.c:612 [inline] (P)
 debug_object_activate+0x344/0x460 lib/debugobjects.c:842 (P)
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 kvfree_call_rcu+0x4c/0x3f0 mm/slab_common.c:1953
 cipso_v4_sock_setattr+0x2fc/0x40c net/ipv4/cipso_ipv4.c:1916
 netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000
 smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581
 smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912
 security_inode_setsecurity+0x118/0x3c0 security/security.c:2706
 __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251
 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295
 vfs_setxattr+0x158/0x2ac fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 file_setxattr+0x1b8/0x294 fs/xattr.c:646
 path_setxattrat+0x2ac/0x320 fs/xattr.c:711
 __do_sys_fsetxattr fs/xattr.c:761 [inline]
 __se_sys_fsetxattr fs/xattr.c:758 [inline]
 __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
irq event stamp: 183
hardirqs last  enabled at (182): [<ffff800080554800>] __up_console_sem kernel/printk/printk.c:344 [inline]
hardirqs last  enabled at (182): [<ffff800080554800>] __console_unlock+0x70/0xc4 kernel/printk/printk.c:2885
hardirqs last disabled at (183): [<ffff80008aef6e24>] el1_brk64+0x1c/0x48 arch/arm64/kernel/entry-common.c:574
softirqs last  enabled at (138): [<ffff8000801fd5e4>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (154): [<ffff800082c87490>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
ODEBUG: active_state active (active state 1) object: 00000000d15d938c object type: rcu_head hint: 0x0
WARNING: CPU: 0 PID: 7470 at lib/debugobjects.c:615 debug_print_object lib/debugobjects.c:612 [inline]
WARNING: CPU: 0 PID: 7470 at lib/debugobjects.c:615 debug_object_active_state+0x28c/0x350 lib/debugobjects.c:1064
Modules linked in:
CPU: 0 UID: 0 PID: 7470 Comm: syz.0.17 Tainted: G        W           6.16.0-rc5-syzkaller-00067-gec4801305969-dirty #0 PREEMPT 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : debug_print_object lib/debugobjects.c:612 [inline]
pc : debug_object_active_state+0x28c/0x350 lib/debugobjects.c:1064
lr : debug_print_object lib/debugobjects.c:612 [inline]
lr : debug_object_active_state+0x28c/0x350 lib/debugobjects.c:1064
sp : ffff80009c3b76c0
x29: ffff80009c3b76d0 x28: ffff80008f671000 x27: dfff800000000000
x26: 0000000000000003 x25: 0000000000000000 x24: ffff0000d8051c08
x23: 0000000000000001 x22: ffff80008afc2440 x21: ffff80008b5399e0
x20: 0000000000000000 x19: ffff8000891ac400 x18: 0000000000000000
x17: 3531643030303030 x16: ffff80008ae63d08 x15: ffff700011ede144
x14: 1ffff00011ede144 x13: 0000000000000004 x12: ffffffffffffffff
x11: ffff700011ede144 x10: 0000000000ff0100 x9 : 5688875a670f5200
x8 : 5688875a670f5200 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80009c3b7018 x4 : ffff80008f766be0 x3 : ffff80008054d314
x2 : 0000000000000000 x1 : 0000000000000202 x0 : 0000000000000000
Call trace:
 debug_print_object lib/debugobjects.c:612 [inline] (P)
 debug_object_active_state+0x28c/0x350 lib/debugobjects.c:1064 (P)
 debug_rcu_head_queue kernel/rcu/rcu.h:237 [inline]
 kvfree_call_rcu+0x64/0x3f0 mm/slab_common.c:1953
 cipso_v4_sock_setattr+0x2fc/0x40c net/ipv4/cipso_ipv4.c:1916
 netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000
 smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581
 smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912
 security_inode_setsecurity+0x118/0x3c0 security/security.c:2706
 __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251
 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295
 vfs_setxattr+0x158/0x2ac fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 file_setxattr+0x1b8/0x294 fs/xattr.c:646
 path_setxattrat+0x2ac/0x320 fs/xattr.c:711
 __do_sys_fsetxattr fs/xattr.c:761 [inline]
 __se_sys_fsetxattr fs/xattr.c:758 [inline]
 __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
irq event stamp: 211
hardirqs last  enabled at (210): [<ffff800080554800>] __up_console_sem kernel/printk/printk.c:344 [inline]
hardirqs last  enabled at (210): [<ffff800080554800>] __console_unlock+0x70/0xc4 kernel/printk/printk.c:2885
hardirqs last disabled at (211): [<ffff80008aef6e24>] el1_brk64+0x1c/0x48 arch/arm64/kernel/entry-common.c:574
softirqs last  enabled at (138): [<ffff8000801fd5e4>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (154): [<ffff800082c87490>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
kvfree_call_rcu(): Double-freed call. rcu_head 00000000d15d938c
WARNING: CPU: 0 PID: 7470 at mm/slab_common.c:1956 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955
Modules linked in:
CPU: 0 UID: 0 PID: 7470 Comm: syz.0.17 Tainted: G        W           6.16.0-rc5-syzkaller-00067-gec4801305969-dirty #0 PREEMPT 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955
lr : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955
sp : ffff80009c3b7730
x29: ffff80009c3b7730 x28: 00000000fffffff5 x27: 1fffe000199fd6e3
x26: dfff800000000000 x25: ffff0000d20c136e x24: 0000000000000017
x23: ffff8000891ac400 x22: 00000000ffffffea x21: ffff8000891ac400
x20: ffff8000891ac400 x19: ffff80008afc2440 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80008ae63d08 x15: ffff700011ede144
x14: 1ffff00011ede144 x13: 0000000000000004 x12: ffffffffffffffff
x11: ffff700011ede144 x10: 0000000000ff0100 x9 : 5688875a670f5200
x8 : 5688875a670f5200 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80009c3b7078 x4 : ffff80008f766be0 x3 : ffff80008054d314
x2 : 0000000000000000 x1 : 0000000000000202 x0 : 0000000000000000
Call trace:
 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 (P)
 cipso_v4_sock_setattr+0x2fc/0x40c net/ipv4/cipso_ipv4.c:1916
 netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000
 smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581
 smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912
 security_inode_setsecurity+0x118/0x3c0 security/security.c:2706
 __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251
 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295
 vfs_setxattr+0x158/0x2ac fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 file_setxattr+0x1b8/0x294 fs/xattr.c:646
 path_setxattrat+0x2ac/0x320 fs/xattr.c:711
 __do_sys_fsetxattr fs/xattr.c:761 [inline]
 __se_sys_fsetxattr fs/xattr.c:758 [inline]
 __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
irq event stamp: 233
hardirqs last  enabled at (232): [<ffff800080554800>] __up_console_sem kernel/printk/printk.c:344 [inline]
hardirqs last  enabled at (232): [<ffff800080554800>] __console_unlock+0x70/0xc4 kernel/printk/printk.c:2885
hardirqs last disabled at (233): [<ffff80008aef6e24>] el1_brk64+0x1c/0x48 arch/arm64/kernel/entry-common.c:574
softirqs last  enabled at (138): [<ffff8000801fd5e4>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (154): [<ffff800082c87490>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


Tested on:

commit:         ec480130 Merge branches 'for-next/core' and 'for-next/..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=114d5bd4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9e99b6fcd403d050
dashboard link: https://syzkaller.appspot.com/bug?extid=40bf00346c3fe40f90f2
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1080a0f0580000