Re: [PATCH] serial: core: Fix a NULL pointer dereference in uart_parse_earlycon()

On 06. 08. 26, 9:29, Greg KH wrote:
> On Thu, Aug 06, 2026 at 03:10:26PM +0800, Xiaochun Li wrote:
>> Panic log below:
>>
>> [    0.000000] BUG: kernel NULL pointer dereference, address: 0000000000000000
>> [    0.000000] #PF: supervisor read access in kernel mode
>> [    0.000000] #PF: error_code(0x0000) - not-present page
>> [    0.000000] PGD 0 P4D 0
>> [    0.000000] Oops: Oops: 0000 [#1] SMP NOPTI
>> [    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.2.0-rc6 #5 PREEMPT(lazy)
>> [    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.q4
>> [    0.000000] RIP: 0010:strncmp+0x1a/0x40
>> [    0.000000] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 85 d2 74 24 31 c0 eb 0d 84 c9
>> [    0.000000] RSP: 0000:ffffffff82c03df0 EFLAGS: 00000246
>> [    0.000000] RAX: 0000000000000000 RBX: ffffffff82c03e20 RCX: ffffffff82c03e20
>> [    0.000000] RDX: 0000000000000005 RSI: ffffffff82acb7a1 RDI: 0000000000000000
>> [    0.000000] RBP: 0000000000000000 R08: 0000000000000040 R09: 0000000000000001
>> [    0.000000] R10: 00000000ffffffea R11: ffffffff82c5cb20 R12: ffffffff82c03e30
>> [    0.000000] R13: ffffffff82c03e2c R14: 0000000000000001 R15: 0000000000014770
>> [    0.000000] FS:  0000000000000000(0000) GS:ffff8882b4460000(0000) knlGS:0000000000000000
>> [    0.000000] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [    0.000000] CR2: 0000000000000000 CR3: 0000000002c30000 CR4: 00000000000000b0
>> [    0.000000] Call Trace:
>> [    0.000000]  <TASK>
>> [    0.000000]  uart_parse_earlycon+0x27/0x140
...
> Odd that this hasn't come up in the decades since it has been present :)

Everyone follows the documentation :P.

-- 
js
suse labs