Re: [PATCH v2] spi: fsl-dspi: fix NULL pointer dereference

[Mark Brown <broonie@kernel.org>]

On Mon, 28 Sep 2020 10:32:38 +0200, Michael Walle wrote:
> Since commit 530b5affc675 ("spi: fsl-dspi: fix use-after-free in remove
> path") this driver causes a kernel oops:
> 
> [    1.891065] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000080
> [    1.899889] Mem abort info:
> [    1.902692]   ESR = 0x96000004
> [    1.905754]   EC = 0x25: DABT (current EL), IL = 32 bits
> [    1.911089]   SET = 0, FnV = 0
> [    1.914156]   EA = 0, S1PTW = 0
> [    1.917303] Data abort info:
> [    1.920193]   ISV = 0, ISS = 0x00000004
> [    1.924044]   CM = 0, WnR = 0
> [    1.927022] [0000000000000080] user address but active_mm is swapper
> [    1.933403] Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [    1.938995] Modules linked in:
> [    1.942060] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc6-next-20200925-00026-gae556cc74e28-dirty #94
> [    1.951838] Hardware name: Kontron SMARC-sAL28 (Single PHY) on SMARC Eval 2.0 carrier (DT)
> [    1.960135] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> [    1.966168] pc : dspi_setup+0xc8/0x2e0
> [    1.969926] lr : dspi_setup+0xbc/0x2e0
> [    1.973684] sp : ffff80001139b930
> [    1.977005] x29: ffff80001139b930 x28: ffff00207a5d2000
> [    1.982338] x27: 0000000000000006 x26: ffff00207a44d410
> [    1.987669] x25: ffff002079c08100 x24: ffff00207a5d2400
> [    1.993000] x23: ffff00207a5d2600 x22: ffff800011169948
> [    1.998332] x21: ffff800010cbcd20 x20: ffff00207a58a800
> [    2.003663] x19: ffff00207a76b700 x18: 0000000000000010
> [    2.008994] x17: 0000000000000001 x16: 0000000000000019
> [    2.014326] x15: ffffffffffffffff x14: 0720072007200720
> [    2.019657] x13: 0720072007200720 x12: ffff8000111fc5e0
> [    2.024989] x11: 0000000000000003 x10: ffff8000111e45a0
> [    2.030320] x9 : 0000000000000000 x8 : ffff00207a76b780
> [    2.035651] x7 : 0000000000000000 x6 : 000000000000003f
> [    2.040982] x5 : 0000000000000040 x4 : ffff80001139b918
> [    2.046313] x3 : 0000000000000001 x2 : 64b62cc917af5100
> [    2.051643] x1 : 0000000000000000 x0 : 0000000000000000
> [    2.056973] Call trace:
> [    2.059425]  dspi_setup+0xc8/0x2e0
> [    2.062837]  spi_setup+0xcc/0x248
> [    2.066160]  spi_add_device+0xb4/0x198
> [    2.069918]  of_register_spi_device+0x250/0x370
> [    2.074462]  spi_register_controller+0x4f4/0x770
> [    2.079094]  dspi_probe+0x5bc/0x7b0
> [    2.082594]  platform_drv_probe+0x5c/0xb0
> [    2.086615]  really_probe+0xec/0x3c0
> [    2.090200]  driver_probe_device+0x60/0xc0
> [    2.094308]  device_driver_attach+0x7c/0x88
> [    2.098503]  __driver_attach+0x60/0xe8
> [    2.102263]  bus_for_each_dev+0x7c/0xd0
> [    2.106109]  driver_attach+0x2c/0x38
> [    2.109692]  bus_add_driver+0x194/0x1f8
> [    2.113538]  driver_register+0x6c/0x128
> [    2.117385]  __platform_driver_register+0x50/0x60
> [    2.122105]  fsl_dspi_driver_init+0x24/0x30
> [    2.126302]  do_one_initcall+0x54/0x2d0
> [    2.130149]  kernel_init_freeable+0x1ec/0x258
> [    2.134520]  kernel_init+0x1c/0x120
> [    2.138018]  ret_from_fork+0x10/0x34
> [    2.141606] Code: 97e0b11d aa0003f3 b4000680 f94006e0 (f9404000)
> [    2.147723] ---[ end trace 26cf63e6cbba33a8 ]---
> [    2.152374] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> [    2.160061] SMP: stopping secondary CPUs
> [    2.163999] Kernel Offset: disabled
> [    2.167496] CPU features: 0x0040022,20006008
> [    2.171777] Memory Limit: none
> [    2.174840] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: fsl-dspi: fix NULL pointer dereference
      commit: 6e3837668e00fb914ac2b43158ef51b027ec385c

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark