On Tue, Dec 17, 2024 at 05:12:07PM +0800, Xu Yang wrote:
> The tcpci_irq() may meet below NULL pointer dereference issue:
>
> [ 2.641851] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
> [ 2.641951] status 0x1, 0x37f
> [ 2.650659] Mem abort info:
> [ 2.656490] ESR = 0x0000000096000004
> [ 2.660230] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 2.665532] SET = 0, FnV = 0
> [ 2.668579] EA = 0, S1PTW = 0
> [ 2.671715] FSC = 0x04: level 0 translation fault
> [ 2.676584] Data abort info:
> [ 2.679459] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
> [ 2.684936] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
> [ 2.689980] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
> [ 2.695284] [0000000000000010] user address but active_mm is swapper
> [ 2.701632] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
> [ 2.707883] Modules linked in:
> [ 2.710936] CPU: 1 UID: 0 PID: 87 Comm: irq/111-2-0051 Not tainted 6.12.0-rc6-06316-g7f63786ad3d1-dirty #4
> [ 2.720570] Hardware name: NXP i.MX93 11X11 EVK board (DT)
> [ 2.726040] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [ 2.732989] pc : tcpci_irq+0x38/0x318
> [ 2.736647] lr : _tcpci_irq+0x14/0x20
> [ 2.740295] sp : ffff80008324bd30
> [ 2.743597] x29: ffff80008324bd70 x28: ffff800080107894 x27: ffff800082198f70
> [ 2.750721] x26: ffff0000050e6680 x25: ffff000004d172ac x24: ffff0000050f0000
> [ 2.757845] x23: ffff000004d17200 x22: 0000000000000001 x21: ffff0000050f0000
> [ 2.764969] x20: ffff000004d17200 x19: 0000000000000000 x18: 0000000000000001
> [ 2.772093] x17: 0000000000000000 x16: ffff80008183d8a0 x15: ffff00007fbab040
> [ 2.779217] x14: ffff00007fb918c0 x13: 0000000000000000 x12: 000000000000017a
> [ 2.786341] x11: 0000000000000001 x10: 0000000000000a90 x9 : ffff80008324bd00
> [ 2.793465] x8 : ffff0000050f0af0 x7 : ffff00007fbaa840 x6 : 0000000000000031
> [ 2.800589] x5 : 000000000000017a x4 : 0000000000000002 x3 : 0000000000000002
> [ 2.807713] x2 : ffff80008324bd3a x1 : 0000000000000010 x0 : 0000000000000000
> [ 2.814838] Call trace:
> [ 2.817273] tcpci_irq+0x38/0x318
> [ 2.820583] _tcpci_irq+0x14/0x20
> [ 2.823885] irq_thread_fn+0x2c/0xa8
> [ 2.827456] irq_thread+0x16c/0x2f4
> [ 2.830940] kthread+0x110/0x114
> [ 2.834164] ret_from_fork+0x10/0x20
> [ 2.837738] Code: f9426420 f9001fe0 d2800000 52800201 (f9400a60)
>
> This may happen on shared irq case. Such as two Type-C ports share one
> irq. After the first port finished tcpci_register_port(), it may trigger
> interrupt. However, if the interrupt comes by chance the 2nd port finishes
> devm_request_threaded_irq(), the 2nd port interrupt handler may be run at
> first. Then the above issue may happen.
>
> devm_request_threaded_irq()
> <-- port1 irq comes
> disable_irq(client->irq);
> tcpci_register_port()
>
> This will restore the logic to the state before commit (77e85107a771 "usb:
> typec: tcpci: support edge irq").
>
> Fixes: 77e85107a771 ("usb: typec: tcpci: support edge irq")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
>
This commit message was not super clear to me. It didn't mention that
it's tcpci->regmap which is the NULL pointer. (Obviously there are a
lot of other NULL pointers, but that's the one which will crash).
Here is something you could add to the commit message:
We cannot register the IRQ handler until after
tcpci_register_port() is called. Otherwise tcpci->regmap and
so many other tcpci pointers are not set up and it leads to
a NULL dereference in tcpci_irq().
regards,
dan carpenter
