[syzbot] [intel-gfx?] general protection fault in i915_pci_probe

[syzbot] [intel-gfx?] general protection fault in i915_pci_probe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    848acc8ffe1b Merge tag 'fsverity-for-linus' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13245bb9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=db96c5ff032f4292a8dc
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=101513b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17245bb9580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-848acc8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6fb497cc0c8d/vmlinux-848acc8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/663ccee34982/bzImage-848acc8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com

e1000e 0000:00:02.0 eth1: removed PHC
e1000e 0000:00:02.0 eth1: NIC Link is Down
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 2 UID: 0 PID: 5932 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:i915_pci_probe+0x57/0x480 drivers/gpu/drm/i915/i915_pci.c:961
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f6 03 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 6c 24 18 4c 8d 6d 1c 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 4c 89 ea 83 e2 07 38 d0 7f 08 84 c0 0f 85 86 03 00 00
RSP: 0018:ffffc900016bf9a0 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffff888023150000 RCX: 0000000000000000
RDX: 0000000000000003 RSI: ffffffff85d8d20d RDI: ffffffff8c43a498
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8c43a480
R13: 000000000000001c R14: ffffffff85d8d1f0 R15: ffff888023150130
FS:  0000555583377500(0000) GS:ffff8880d5fd8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff49e597e9c CR3: 0000000023b2c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332
 pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 device_driver_attach+0xd1/0x220 drivers/base/dd.c:1203
 bind_store+0xf4/0x190 drivers/base/bus.c:267
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f246059e019
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:00007ffe32b38f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2460825fa0 RCX: 00007f246059e019
RDX: 000000000000000d RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007f246063500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2460825fac R14: 00007f2460825fa0 R15: 00007f2460825fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:i915_pci_probe+0x57/0x480 drivers/gpu/drm/i915/i915_pci.c:961
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f6 03 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 6c 24 18 4c 8d 6d 1c 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 4c 89 ea 83 e2 07 38 d0 7f 08 84 c0 0f 85 86 03 00 00
RSP: 0018:ffffc900016bf9a0 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffff888023150000 RCX: 0000000000000000
RDX: 0000000000000003 RSI: ffffffff85d8d20d RDI: ffffffff8c43a498
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8c43a480
R13: 000000000000001c R14: ffffffff85d8d1f0 R15: ffff888023150130
FS:  0000555583377500(0000) GS:ffff8880d5fd8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff49e597e9c CR3: 0000000023b2c000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	89 fa                	mov    %edi,%edx
   2:	48 c1 ea 03          	shr    $0x3,%rdx
   6:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   a:	0f 85 f6 03 00 00    	jne    0x406
  10:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  17:	fc ff df
  1a:	49 8b 6c 24 18       	mov    0x18(%r12),%rbp
  1f:	4c 8d 6d 1c          	lea    0x1c(%rbp),%r13
  23:	4c 89 ea             	mov    %r13,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	4c 89 ea             	mov    %r13,%rdx
  31:	83 e2 07             	and    $0x7,%edx
  34:	38 d0                	cmp    %dl,%al
  36:	7f 08                	jg     0x40
  38:	84 c0                	test   %al,%al
  3a:	0f 85 86 03 00 00    	jne    0x3c6


---
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Forwarded: [PATCH] drm/i915: Guard against NULL driver_data in i915_pci_probe()

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] drm/i915: Guard against NULL driver_data in i915_pci_probe()
Author: kartikey406@gmail.com

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


pci_match_device() can return the dummy pci_device_id_any entry
when a device is force-bound via sysfs driver_override, in which
case ->driver_data is unset (NULL). i915_pci_probe() casts it to
struct intel_device_info * unconditionally and dereferences
intel_info->require_force_probe, causing a NULL-ptr-deref.

Reported-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com
Tested-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=db96c5ff032f4292a8dc
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 drivers/gpu/drm/i915/i915_pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 82415af47d54..2f03f95945f1 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -958,6 +958,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		(struct intel_device_info *) ent->driver_data;
 	int err;
 
+	if (!intel_info)
+		return -ENODEV;
+
 	if (intel_info->require_force_probe && !id_forced(pdev->device)) {
 		dev_info(&pdev->dev,
 			 "Your graphics device %04x is not properly supported by i915 in this\n"
-- 
2.34.1

Re: [syzbot] [intel-gfx?] general protection fault in i915_pci_probe

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com
Tested-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com

Tested on:

commit:         0d839570 Merge tag 'soc-fixes-7.2-2' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=104d8e49580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=db96c5ff032f4292a8dc
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15768132580000

Note: testing is done by a robot and is best-effort only.