Messages in this thread | | | Date | Mon, 10 Oct 2022 19:02:46 +0200 | From | Greg KH <> | Subject | Re: [PATCH] Speakup: fix a segfault caused by switching consoles |
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On Mon, Oct 10, 2022 at 09:57:20PM +0500, Mushahid Hussain wrote: > This patch fixes a segfault by adding a null check on synth in > speakup_con_update(). The segfault can be reproduced as follows: > > - Login into a text console > > - Load speakup and speakup_soft modules > > - Remove speakup_soft > > - Switch to a graphics console > > This is caused by lack of a null check on `synth` in > speakup_con_update(). > > Here's the sequence that causes the segfault: > > - When we remove the speakup_soft, synth_release() sets the synth > to null. > > - After that, when we change the virtual console to graphics > console, vt_notifier_call() is fired, which then calls > speakup_con_update(). > > - Inside speakup_con_update() there's no null check on synth, > so it calls synth_printf(). > > - Inside synth_printf(), synth_buffer_add() and synth_start(), > both access synth, when it is null and causing a segfault. > > Therefore adding a null check on synth solves the issue. > > Signed-off-by: Mushahid Hussain <mushi.shar@gmail.com> > Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> > --- > drivers/accessibility/speakup/main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
What commit id does this fix? Should it go to stable kernels?
thanks,
greg k-h
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