When unexpected situation happened (e.g. tx/rx irq happened while DMAC is used), the usbhsf_pkt_handler() was possible to cause NULL pointer dereference like the followings: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: Oops: 80000007 [#1] SMP ARM Modules linked in: usb_f_acm u_serial g_serial libcomposite CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.5.0-rc6-00842-gac57066-dirty #63 Hardware name: Generic R8A7790 (Flattened Device Tree) task: c0729c00 ti: c0724000 task.ti: c0724000 PC is at 0x0 LR is at usbhsf_pkt_handler+0xac/0x118 pc : [<00000000>] lr : [<c03257e0>] psr: 60000193 sp : c0725db8 ip : 00000000 fp : c0725df4 r10: 00000001 r9 : 00000193 r8 : ef3ccab4 r7 : ef3cca10 r6 : eea4586c r5 : 00000000 r4 : ef19ceb4 r3 : 00000000 r2 : 0000009c r1 : c0725dc4 r0 : ef19ceb4 This patch adds a condition to avoid the dereference. Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> --- drivers/usb/renesas_usbhs/fifo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c index b4de70e..0c25c01 100644 --- a/drivers/usb/renesas_usbhs/fifo.c +++ b/drivers/usb/renesas_usbhs/fifo.c @@ -190,7 +190,8 @@ static int usbhsf_pkt_handler(struct usbhs_pipe *pipe, int type) goto __usbhs_pkt_handler_end; } - ret = func(pkt, &is_done); + if (likely(func)) + ret = func(pkt, &is_done); if (is_done) __usbhsf_pkt_del(pkt); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
