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SubjectRe: [PATCH v2] ppdev: fix double-free of pp->pdev->name
On Sun, Oct 30, 2016 at 11:19:24PM +0100, Jann Horn wrote:
> free_pardevice() is called by parport_unregister_device() and already frees
> pp->pdev->name, don't try to do it again.
>
> This bug causes kernel crashes.
>
> I found and verified this with KASAN and some added pr_emerg()s:
>
> [ 60.316568] pp_release: pp->pdev->name == ffff88039cb264c0
> [ 60.316692] free_pardevice: freeing par_dev->name at ffff88039cb264c0
> [ 60.316706] pp_release: kfree(ffff88039cb264c0)
> [ 60.316714] ==========================================================
> [ 60.316722] BUG: Double free or freeing an invalid pointer
> [ 60.316731] Unexpected shadow byte: 0xFB
> [ 60.316801] Object at ffff88039cb264c0, in cache kmalloc-32 size: 32
> [ 60.316813] Allocated:
> [ 60.316824] PID = 1695
> [ 60.316869] Freed:
> [ 60.316880] PID = 1695
> [ 60.316935] ==========================================================
>
> Signed-off-by: Jann Horn <jann@thejh.net>
> ---
> drivers/char/ppdev.c | 3 ---
> 1 file changed, 3 deletions(-)

Sudip, I need an ack here before I can take this...

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