Re: [PATCH] usb: phy: msm: fix error handling in probe.

[Felipe Balbi <balbi@kernel.org>]

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Hi,

Srinivas Kandagatla <srinivas.kandagatla@linaro.org> writes:
> This driver registers for extcon events as part of its probe, but
> never unregisters them in case of error in the probe path.
>
> There were multiple issues noticed due to this missing error handling.
> One of them is random crashes if the regulators are not ready yet by the
> time probe is invoked.
>
> Ivan's previous attempt [1] to fix this issue, did not really address
> all the failure cases like regualtor failures.
>
> [1] https://lkml.org/lkml/2015/9/7/62
>
> Without this patch the kernel would carsh with log:
> ...
> Unable to handle kernel paging request at virtual address 17d78410
> pgd = ffffffc001a5c000
> [17d78410] *pgd=00000000b6806003, *pud=00000000b6806003, *pmd=0000000000000000
> Internal error: Oops: 96000005 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted 4.4.0+ #48
> Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> Workqueue: deferwq deferred_probe_work_func
> task: ffffffc03686e900 ti: ffffffc0368b0000 task.ti: ffffffc0368b0000
> PC is at raw_notifier_chain_register+0x1c/0x44
> LR is at extcon_register_notifier+0x88/0xc8
> pc : [<ffffffc0000da43c>] lr : [<ffffffc000606298>] pstate: 80000085
> sp : ffffffc0368b3a70
> x29: ffffffc0368b3a70 x28: ffffffc03680c310
> x27: ffffffc035518000 x26: ffffffc035518000
> x25: ffffffc03bfa20e0 x24: ffffffc035580a18
> x23: 0000000000000000 x22: ffffffc035518458
> x21: ffffffc0355e9a60 x20: ffffffc035518000
> x19: 0000000000000000 x18: 0000000000000028
> x17: 0000000000000003 x16: ffffffc0018153c8
> x15: 0000000000000001 x14: ffffffc03686f0f8
> x13: ffffffc03686f0f8 x12: 0000000000000003
> x11: 0000000000000001 x10: 0000000000000001
> x9 : ffffffc03686f0f8 x8 : 0000e3872014c1a1
> x7 : 0000000000000028 x6 : 0000000000000000
> x5 : 0000000000000001 x4 : 0000000000000000
> x3 : 00000000354fb170 x2 : 0000000017d78400
> x1 : ffffffc0355e9a60 x0 : ffffffc0354fb268
>

you need to "blame" a commit with:

Fixes: First-12-characters-of-commit-hash ("commit subject line")

and if the failing commit sits in a released kernel, you also need to
add:

Cc: <stable@vger.kernel.org> # vX.Y

-- 
balbi

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