[syzbot] [usb?] general protection fault in ucsi_acpi_probe

[syzbot] [usb?] general protection fault in ucsi_acpi_probe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    4477a78374a5 Add linux-next specific files for 20260814
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=114036c6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9b32a36dd637b06f
dashboard link: https://syzkaller.appspot.com/bug?extid=23cf45a9fce78e4e0dc1
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13c60679580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/994c1c8c560e/disk-4477a783.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cd54543d69ae/vmlinux-4477a783.xz
kernel image: https://storage.googleapis.com/syzbot-assets/407cdf8f3fc2/bzImage-4477a783.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+23cf45a9fce78e4e0dc1@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc00000000e5: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000728-0x000000000000072f]
CPU: 1 UID: 0 PID: 5814 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:ucsi_acpi_probe+0x6c/0x4b0 drivers/usb/typec/ucsi/ucsi_acpi.c:199
Code: 89 74 24 08 4c 8b 23 4c 89 e7 e8 ef df 54 fd 49 83 c4 f0 45 31 f6 84 c0 4d 0f 45 f4 49 81 c6 2c 07 00 00 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 16 04 00 00 41 8b 2e 31 ff 89 ee e8 cb
RSP: 0018:ffffc9000272fab8 EFLAGS: 00010203
RAX: 00000000000000e5 RBX: ffff88801db68430 RCX: ffff88807f249f40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802b52e5a3 R09: 1ffff110056a5cb4
R10: dffffc0000000000 R11: ffffffff87e620e0 R12: fffffffffffffff0
R13: dffffc0000000000 R14: 000000000000072c R15: 1ffff11003b6d086
FS:  000055555ee6f500(0000) GS:ffff888124df8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb722c70000 CR3: 0000000075912000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 platform_probe+0xf9/0x190 drivers/base/platform.c:1507
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 device_driver_attach+0xe0/0x1d0 drivers/base/dd.c:1203
 bind_store+0x1d0/0x220 drivers/base/bus.c:267
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb722d9e0d9
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:00007fff7bf8acb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb723025fa0 RCX: 00007fb722d9e0d9
RDX: 0000000000000007 RSI: 0000200000000180 RDI: 0000000000000004
RBP: 00007fb722e35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb723025fac R14: 00007fb723025fa0 R15: 00007fb723025fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ucsi_acpi_probe+0x6c/0x4b0 drivers/usb/typec/ucsi/ucsi_acpi.c:199
Code: 89 74 24 08 4c 8b 23 4c 89 e7 e8 ef df 54 fd 49 83 c4 f0 45 31 f6 84 c0 4d 0f 45 f4 49 81 c6 2c 07 00 00 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 16 04 00 00 41 8b 2e 31 ff 89 ee e8 cb
RSP: 0018:ffffc9000272fab8 EFLAGS: 00010203
RAX: 00000000000000e5 RBX: ffff88801db68430 RCX: ffff88807f249f40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802b52e5a3 R09: 1ffff110056a5cb4
R10: dffffc0000000000 R11: ffffffff87e620e0 R12: fffffffffffffff0
R13: dffffc0000000000 R14: 000000000000072c R15: 1ffff11003b6d086
FS:  000055555ee6f500(0000) GS:ffff888124cf8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb722fee000 CR3: 0000000075912000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 74 24 08          	mov    %esi,0x8(%rsp)
   4:	4c 8b 23             	mov    (%rbx),%r12
   7:	4c 89 e7             	mov    %r12,%rdi
   a:	e8 ef df 54 fd       	call   0xfd54dffe
   f:	49 83 c4 f0          	add    $0xfffffffffffffff0,%r12
  13:	45 31 f6             	xor    %r14d,%r14d
  16:	84 c0                	test   %al,%al
  18:	4d 0f 45 f4          	cmovne %r12,%r14
  1c:	49 81 c6 2c 07 00 00 	add    $0x72c,%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 16 04 00 00    	jne    0x44d
  37:	41 8b 2e             	mov    (%r14),%ebp
  3a:	31 ff                	xor    %edi,%edi
  3c:	89 ee                	mov    %ebp,%esi
  3e:	e8                   	.byte 0xe8
  3f:	cb                   	lret


---
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Forwarded: [PATCH] usb: typec: ucsi_acpi: fix NULL pointer dereference in ucsi_acpi_probe()

[syzbot]

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***

Subject: [PATCH] usb: typec: ucsi_acpi: fix NULL pointer dereference in ucsi_acpi_probe()
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


ucsi_acpi_probe() dereferences the ACPI companion device pointer
returned by ACPI_COMPANION() without checking it for NULL. While
this driver is normally probed through ACPI device enumeration
where a companion is always present, a platform_device can also be
manually bound to any platform driver via the sysfs 'bind' file
(bind_store() -> bus_find_device() -> driver_attach_device()),
which matches purely on device name and bypasses ACPI matching.

If ucsi_acpi is bound this way to a platform device with no ACPI
companion, ACPI_COMPANION() returns NULL and the subsequent
adev->dep_unmet access dereferences a NULL pointer, resulting in a
general protection fault.

Add a NULL check for adev immediately after it is obtained and
before any resource allocation, returning -ENODEV to decline
binding cleanly.

Reported-by: syzbot+23cf45a9fce78e4e0dc1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=23cf45a9fce78e4e0dc1
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 drivers/usb/typec/ucsi/ucsi_acpi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
index 18286d3e9cc5..9fe4ba43afea 100644
--- a/drivers/usb/typec/ucsi/ucsi_acpi.c
+++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
@@ -196,6 +196,9 @@ static int ucsi_acpi_probe(struct platform_device *pdev)
 	acpi_status status;
 	int ret;
 
+	if (!adev)
+		return -ENODEV;
+
 	if (adev->dep_unmet)
 		return -EPROBE_DEFER;
 
-- 
2.34.1