2026-03-25 10:27:50
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved:
i2c: i801: Revert "i2c: i801: replace acpi_lock with I2C bus lock"
This reverts commit f707d6b9e7c18f669adfdb443906d46cfbaaa0c1.
Under rare circumstances, multiple udev threads can collect i801 device
info on boot and walk i801_acpi_io_handler somewhat concurrently. The
first will note the area is reserved by acpi to prevent further touches.
This ultimately causes the area to be deregistered. The second will
enter i801_acpi_io_handler after the area is unregistered but before a
check can be made that the area is unregistered. i2c_lock_bus relies on
the now unregistered area containing lock_ops to lock the bus. The end
result is a kernel panic on boot with the following backtrace;
[ 14.971872] ioatdma 0000:09:00.2: enabling device (0100 -> 0102)
[ 14.971873] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 14.971880] #PF: supervisor read access in kernel mode
[ 14.971884] #PF: error_code(0x0000) - not-present page
[ 14.971887] PGD 0 P4D 0
[ 14.971894] Oops: 0000 [#1] PREEMPT SMP PTI
[ 14.971900] CPU: 5 PID: 956 Comm: systemd-udevd Not tainted 5.14.0-611.5.1.el9_7.x86_64 #1
[ 14.971905] Hardware name: XXXXXXXXXXXXXXXXXXXXXXX BIOS 1.20.10.SV91 01/30/2023
[ 14.971908] RIP: 0010:i801_acpi_io_handler+0x2d/0xb0 [i2c_i801]
[ 14.971929] Code: 00 00 49 8b 40 20 41 57 41 56 4d 8b b8 30 04 00 00 49 89 ce 41 55 41 89 d5 41 54 49 89 f4 be 02 00 00 00 55 4c 89 c5 53 89 fb <48> 8b 00 4c 89 c7 e8 18 61 54 e9 80 bd 80 04 00 00 00 75 09 4c 3b
[ 14.971933] RSP: 0018:ffffbaa841483838 EFLAGS: 00010282
[ 14.971938] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff9685e01ba568
[ 14.971941] RDX: 0000000000000008 RSI: 0000000000000002 RDI: 0000000000000000
[ 14.971944] RBP: ffff9685ca22f028 R08: ffff9685ca22f028 R09: ffff9685ca22f028
[ 14.971948] R10: 000000000000000b R11: 0000000000000580 R12: 0000000000000580
[ 14.971951] R13: 0000000000000008 R14: ffff9685e01ba568 R15: ffff9685c222f000
[ 14.971954] FS: 00007f8287c0ab40(0000) GS:ffff96a47f940000(0000) knlGS:0000000000000000
[ 14.971959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 14.971963] CR2: 0000000000000000 CR3: 0000000168090001 CR4: 00000000003706f0
[ 14.971966] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 14.971968] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 14.971972] Call Trace:
[ 14.971977]