[syzbot] [crypto?] BUG: sleeping function called from invalid context in crypto_put_default_null_skcipher

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a024e377efed net: llc: reset skb->transport_header
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15c7f0b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6a2b862bf4a5409f
dashboard link: https://syzkaller.appspot.com/bug?extid=b3e02953598f447d4d2a
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=14bce818580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12bce818580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f2ea524d69fe/disk-a024e377.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b39d227b097d/vmlinux-a024e377.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8ee66636253f/bzImage-a024e377.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b3e029...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:562
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/0
preempt_count: 101, expected: 0
RCU nest depth: 0, expected: 0
1 lock held by swapper/0/0:
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2561 [inline]
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_core+0xa37/0x17a0 kernel/rcu/tree.c:2823
Preemption disabled at:
[<ffffffff8bc9a85d>] schedule_preempt_disabled+0x1d/0x30 kernel/sched/core.c:6906
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc3-syzkaller-00174-ga024e377efed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
__might_resched+0x5d4/0x780 kernel/sched/core.c:8758
__mutex_lock_common kernel/locking/mutex.c:562 [inline]
__mutex_lock+0x131/0xee0 kernel/locking/mutex.c:735
crypto_put_default_null_skcipher+0x18/0x70 crypto/crypto_null.c:179
aead_release+0x3d/0x50 crypto/algif_aead.c:489
alg_do_release crypto/af_alg.c:118 [inline]
alg_sock_destruct+0x86/0xc0 crypto/af_alg.c:502
__sk_destruct+0x58/0x5f0 net/core/sock.c:2260
rcu_do_batch kernel/rcu/tree.c:2567 [inline]
rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
__do_softirq kernel/softirq.c:595 [inline]
invoke_softirq kernel/softirq.c:435 [inline]
__irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 00 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 15 c1 a0 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e607ca8 EFLAGS: 00000246
RAX: ffffffff8e6965c0 RBX: ffff888140ee4064 RCX: 000000000001ace9
RDX: 0000000000000001 RSI: ffff888140ee4000 RDI: ffff888140ee4064
RBP: 000000000003a9f8 R08: ffff8880b8637cdb R09: 1ffff110170c6f9b
R10: dffffc0000000000 R11: ffffffff8bc8bc80 R12: ffff88814628d000
R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f1217a0
acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699
cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268
cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:230 [inline]
do_idle+0x372/0x5c0 kernel/sched/idle.c:325
cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
rest_init+0x2dc/0x300 init/main.c:747
start_kernel+0x47f/0x500 init/main.c:1102
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x147
</TASK>

=============================
[ BUG: Invalid wait context ]
6.13.0-rc3-syzkaller-00174-ga024e377efed #0 Tainted: G W
-----------------------------
swapper/0/0 is trying to lock:
ffffffff8f035d88 (crypto_default_null_skcipher_lock){+.+.}-{4:4}, at: crypto_put_default_null_skcipher+0x18/0x70 crypto/crypto_null.c:179
other info that might help us debug this:
context-{3:3}
1 lock held by swapper/0/0:
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2561 [inline]
#0: ffffffff8e937ba0 (rcu_callback){....}-{0:0}, at: rcu_core+0xa37/0x17a0 kernel/rcu/tree.c:2823
stack backtrace:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.13.0-rc3-syzkaller-00174-ga024e377efed #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline]
check_wait_context kernel/locking/lockdep.c:4898 [inline]
__lock_acquire+0x15a8/0x2100 kernel/locking/lockdep.c:5176
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
crypto_put_default_null_skcipher+0x18/0x70 crypto/crypto_null.c:179
aead_release+0x3d/0x50 crypto/algif_aead.c:489
alg_do_release crypto/af_alg.c:118 [inline]
alg_sock_destruct+0x86/0xc0 crypto/af_alg.c:502
__sk_destruct+0x58/0x5f0 net/core/sock.c:2260
rcu_do_batch kernel/rcu/tree.c:2567 [inline]
rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
__do_softirq kernel/softirq.c:595 [inline]
invoke_softirq kernel/softirq.c:435 [inline]
__irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 00 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 15 c1 a0 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e607ca8 EFLAGS: 00000246
RAX: ffffffff8e6965c0 RBX: ffff888140ee4064 RCX: 000000000001ace9
RDX: 0000000000000001 RSI: ffff888140ee4000 RDI: ffff888140ee4064
RBP: 000000000003a9f8 R08: ffff8880b8637cdb R09: 1ffff110170c6f9b
R10: dffffc0000000000 R11: ffffffff8bc8bc80 R12: ffff88814628d000
R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f1217a0
acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699
cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268
cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:230 [inline]
do_idle+0x372/0x5c0 kernel/sched/idle.c:325
cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
rest_init+0x2dc/0x300 init/main.c:747
start_kernel+0x47f/0x500 init/main.c:1102
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x147
</TASK>
----------------
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: 65 48 8b 04 25 00 d6 mov %gs:0x3d600,%rax
10: 03 00
12: 48 f7 00 08 00 00 00 testq $0x8,(%rax)
19: 75 10 jne 0x2b
1b: 66 90 xchg %ax,%ax
1d: 0f 00 2d 15 c1 a0 00 verw 0xa0c115(%rip) # 0xa0c139
24: f3 0f 1e fa endbr64
28: fb sti
29: f4 hlt
* 2a: fa cli <-- trapping instruction
2b: c3 ret
2c: cc int3
2d: cc int3
2e: cc int3
2f: cc int3
30: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
37: 00 00
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop


---
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[Herbert Xu]

On Mon, Dec 30, 2024 at 11:22:28AM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: a024e377efed net: llc: reset skb->transport_header
> git tree: net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=15c7f0b0580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=6a2b862bf4a5409f
> dashboard link: https://syzkaller.appspot.com/bug?extid=b3e02953598f447d4d2a
> 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=14bce818580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12bce818580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f2ea524d69fe/disk-a024e377.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b39d227b097d/vmlinux-a024e377.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/8ee66636253f/bzImage-a024e377.xz

---8<---
As the null algorithm may be freed in softirq context through
af_alg, use spin locks instead of mutexes to protect the default
null algorithm.

Reported-by: syzbot+b3e029...@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <her...@gondor.apana.org.au>

diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c
index 5b84b0f7cc17..337867028653 100644
--- a/crypto/crypto_null.c
+++ b/crypto/crypto_null.c
@@ -17,10 +17,10 @@
#include <crypto/internal/skcipher.h>
#include <linux/init.h>
#include <linux/module.h>
-#include <linux/mm.h>
+#include <linux/spinlock.h>
#include <linux/string.h>

-static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
+static DEFINE_SPINLOCK(crypto_default_null_skcipher_lock);
static struct crypto_sync_skcipher *crypto_default_null_skcipher;
static int crypto_default_null_skcipher_refcnt;

@@ -152,23 +152,32 @@ MODULE_ALIAS_CRYPTO("cipher_null");

struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
{
+ struct crypto_sync_skcipher *ntfm = NULL;
struct crypto_sync_skcipher *tfm;

- mutex_lock(&crypto_default_null_skcipher_lock);
+ spin_lock_bh(&crypto_default_null_skcipher_lock);
tfm = crypto_default_null_skcipher;

if (!tfm) {
- tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
- if (IS_ERR(tfm))
- goto unlock;
+ spin_unlock_bh(&crypto_default_null_skcipher_lock);

- crypto_default_null_skcipher = tfm;
+ ntfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
+ if (IS_ERR(ntfm))
+ return ntfm;
+
+ spin_lock_bh(&crypto_default_null_skcipher_lock);
+ tfm = crypto_default_null_skcipher;
+ if (!tfm) {
+ tfm = ntfm;
+ ntfm = NULL;
+ crypto_default_null_skcipher = tfm;
+ }
}

crypto_default_null_skcipher_refcnt++;
+ spin_unlock_bh(&crypto_default_null_skcipher_lock);

-unlock:
- mutex_unlock(&crypto_default_null_skcipher_lock);
+ crypto_free_sync_skcipher(ntfm);

return tfm;
}
@@ -176,12 +185,16 @@ EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);

void crypto_put_default_null_skcipher(void)
{
- mutex_lock(&crypto_default_null_skcipher_lock);
+ struct crypto_sync_skcipher *tfm = NULL;
+
+ spin_lock_bh(&crypto_default_null_skcipher_lock);
if (!--crypto_default_null_skcipher_refcnt) {
- crypto_free_sync_skcipher(crypto_default_null_skcipher);
+ tfm = crypto_default_null_skcipher;
crypto_default_null_skcipher = NULL;
}
- mutex_unlock(&crypto_default_null_skcipher_lock);
+ spin_unlock_bh(&crypto_default_null_skcipher_lock);
+
+ crypto_free_sync_skcipher(tfm);
}
EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);

--
Email: Herbert Xu <her...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt