Am Freitag, dem 15.10.2021 um 15:46 +0800 schrieb Miles Chen:
> After merging commit ed4246d37f3b ("scsi: sd: REQUEST SENSE for
> BLIST_IGN_MEDIA_CHANGE devices in runtime_resume()"), I hit the
> following crash on my device.
>
> static int sd_resume_runtime(struct device *dev)
> {
> struct scsi_disk *sdkp = dev_get_drvdata(dev);
> struct scsi_device *sdp = sdkp->device; // sdkp == NULL and
> crash
>
> if (sdp->ignore_media_change) {
> ...
> }
>
> I checked sd_resume() and found that sdkp is possbile to be NULL, and
> there is a null pointer test in sd_resume() for this case.
> To fix this crash, follow sd_resume() to test if sdkp is NULL
> before dereferencing it.
>
> Crash:
> [ 4.695171][ T151] Unable to handle kernel NULL pointer
> dereference at virtual address 0000000000000008
> [ 4.696591][ T151] Mem abort info:
> [ 4.697919][ T151] ESR = 0x96000005
> [ 4.699692][ T151] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 4.701990][ T151] SET = 0, FnV = 0
> [ 4.702513][ T151] EA = 0, S1PTW = 0
> [ 4.704431][ T151] FSC = 0x05: level 1 translation fault
> [ 4.705254][ T151] Data abort info:
> [ 4.705806][ T151] ISV = 0, ISS = 0x00000005
> [ 4.706484][ T151] CM = 0, WnR = 0
> [ 4.707048][ T151] [0000000000000008] user address but active_mm
> is swapper
> [ 4.710577][ T151] Internal error: Oops: 96000005 [#1] PREEMPT
> SMP
> [ 4.832361][ T151] Kernel Offset: 0x12acc80000 from
> 0xffffffc010000000
> [ 4.833254][ T151] PHYS_OFFSET: 0x40000000
> [ 4.833814][ T151] pstate: 80400005 (Nzcv daif +PAN -UAO)
> [ 4.834546][ T151] pc : sd_resume_runtime+0x20/0x14c
> [ 4.835227][ T151] lr : scsi_runtime_resume+0x84/0xe4
> [ 4.835916][ T151] sp : ffffffc0110db8d0
> [ 4.836450][ T151] x29: ffffffc0110db8d0 x28: 0000000000000001
> [ 4.837258][ T151] x27: ffffff80c0bd1ac0 x26: ffffff80c0bd1ad0
> [ 4.838063][ T151] x25: ffffff80cea7e448 x24: ffffffd2bf961000
> [ 4.838867][ T151] x23: ffffffd2be69f838 x22: ffffffd2bd9dfb4c
> [ 4.839670][ T151] x21: 0000000000000000 x20: ffffff80cea7e000
> [ 4.840474][ T151] x19: ffffff80cea7e260 x18: ffffffc0110dd078
> [ 4.841277][ T151] x17: 00000000658783d9 x16: 0000000051469dac
> [ 4.842081][ T151] x15: 00000000b87f6327 x14: 0000000068fd680d
> [ 4.842885][ T151] x13: ffffff80c0bd2470 x12: ffffffd2bfa7f5f0
> [ 4.843688][ T151] x11: 0000000000000078 x10: 0000000000000001
> [ 4.844492][ T151] x9 : 00000000000000b1 x8 : ffffffd2be69f88c
> [ 4.845295][ T151] x7 : ffffffd2bd9e0e5c x6 : 0000000000000000
> [ 4.846099][ T151] x5 : 0000000000000080 x4 : 0000000000000001
> [ 4.846902][ T151] x3 : 68fd680dfe4ebe5e x2 : 0000000000000003
> [ 4.847706][ T151] x1 : ffffffd2bf7f9380 x0 : ffffff80cea7e260
> [ 4.856708][ T151] die+0x16c/0x59c
> [ 4.857191][ T151] __do_kernel_fault+0x1e8/0x210
> [ 4.857833][ T151] do_page_fault+0xa4/0x654
> [ 4.858418][ T151] do_translation_fault+0x6c/0x1b0
> [ 4.859083][ T151] do_mem_abort+0x68/0x10c
> [ 4.859655][ T151] el1_abort+0x40/0x64
> [ 4.860182][ T151] el1h_64_sync_handler+0x54/0x88
> [ 4.860834][ T151] el1h_64_sync+0x7c/0x80
> [ 4.861395][ T151] sd_resume_runtime+0x20/0x14c
> [ 4.862025][ T151] scsi_runtime_resume+0x84/0xe4
> [ 4.862667][ T151] __rpm_callback+0x1f4/0x8cc
> [ 4.863275][ T151] rpm_resume+0x7e8/0xaa4
> [ 4.863836][ T151] __pm_runtime_resume+0xa0/0x110
> [ 4.864489][ T151] sd_probe+0x30/0x428
> [ 4.865016][ T151] really_probe+0x14c/0x500
> [ 4.865602][ T151] __driver_probe_device+0xb4/0x18c
> [ 4.866278][ T151] driver_probe_device+0x60/0x2c4
> [ 4.866931][ T151] __device_attach_driver+0x228/0x2bc
> [ 4.867630][ T151] __device_attach_async_helper+0x154/0x21c
> [ 4.868398][ T151] async_run_entry_fn+0x5c/0x1c4
> [ 4.869038][ T151] process_one_work+0x3ac/0x590
> [ 4.869670][ T151] worker_thread+0x320/0x758
> [ 4.870265][ T151] kthread+0x2e8/0x35c
> [ 4.870792][ T151] ret_from_fork+0x10/0x20
>
> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
> Fixes: ed4246d37f3b ("scsi: sd: REQUEST SENSE for
> BLIST_IGN_MEDIA_CHANGE devices in runtime_resume()")
> Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
> ---
> drivers/scsi/sd.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 523bf2fdc253..fce63335084e 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -3683,7 +3683,12 @@ static int sd_resume(struct device *dev)
> static int sd_resume_runtime(struct device *dev)
> {
> struct scsi_disk *sdkp = dev_get_drvdata(dev);
> - struct scsi_device *sdp = sdkp->device;
> + struct scsi_device *sdp;
> +
> + if (!sdkp) /* E.g.: runtime resume at the start of
> sd_probe() */
> + return 0;
> +
> + sdp = sdkp->device;
>
> if (sdp->ignore_media_change) {
> /* clear the device's sense data */
I'm fine with this, thank you.
Reviewed-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
