| Message ID | 20200506181902.193290-1-christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [V2] video: fbdev: w100fb: Fix a potential double free. | expand |
Hi Christophe On Wed, May 06, 2020 at 08:19:02PM +0200, Christophe JAILLET wrote: > Some memory is vmalloc'ed in the 'w100fb_save_vidmem' function and freed in > the 'w100fb_restore_vidmem' function. (these functions are called > respectively from the 'suspend' and the 'resume' functions) > > However, it is also freed in the 'remove' function. > > In order to avoid a potential double free, set the corresponding pointer > to NULL once freed in the 'w100fb_restore_vidmem' function. > > Fixes: aac51f09d96a ("[PATCH] w100fb: Rewrite for platform independence") > Cc: Richard Purdie <rpurdie@rpsys.net> > Cc: Antonino Daplas <adaplas@pol.net> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > Cc: <stable@vger.kernel.org> # v2.6.14+ > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Thanks for the quick v2. Applied to drm-misc-next. Sam > --- > v2: - Add Cc: tags > - Reword the commit message to give the names of the functions that > allocate and free the memory. These functions are called from the > suspend and resume function. > --- > drivers/video/fbdev/w100fb.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/video/fbdev/w100fb.c b/drivers/video/fbdev/w100fb.c > index 2d6e2738b792..d96ab28f8ce4 100644 > --- a/drivers/video/fbdev/w100fb.c > +++ b/drivers/video/fbdev/w100fb.c > @@ -588,6 +588,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par) > memsize=par->mach->mem->size; > memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_extmem, memsize); > vfree(par->saved_extmem); > + par->saved_extmem = NULL; > } > if (par->saved_intmem) { > memsize=MEM_INT_SIZE; > @@ -596,6 +597,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par) > else > memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_intmem, memsize); > vfree(par->saved_intmem); > + par->saved_intmem = NULL; > } > } > > -- > 2.25.1
diff --git a/drivers/video/fbdev/w100fb.c b/drivers/video/fbdev/w100fb.c index 2d6e2738b792..d96ab28f8ce4 100644 --- a/drivers/video/fbdev/w100fb.c +++ b/drivers/video/fbdev/w100fb.c @@ -588,6 +588,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par) memsize=par->mach->mem->size; memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_extmem, memsize); vfree(par->saved_extmem); + par->saved_extmem = NULL; } if (par->saved_intmem) { memsize=MEM_INT_SIZE; @@ -596,6 +597,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par) else memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_intmem, memsize); vfree(par->saved_intmem); + par->saved_intmem = NULL; } }
Some memory is vmalloc'ed in the 'w100fb_save_vidmem' function and freed in the 'w100fb_restore_vidmem' function. (these functions are called respectively from the 'suspend' and the 'resume' functions) However, it is also freed in the 'remove' function. In order to avoid a potential double free, set the corresponding pointer to NULL once freed in the 'w100fb_restore_vidmem' function. Fixes: aac51f09d96a ("[PATCH] w100fb: Rewrite for platform independence") Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Antonino Daplas <adaplas@pol.net> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: <stable@vger.kernel.org> # v2.6.14+ Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- v2: - Add Cc: tags - Reword the commit message to give the names of the functions that allocate and free the memory. These functions are called from the suspend and resume function. --- drivers/video/fbdev/w100fb.c | 2 ++ 1 file changed, 2 insertions(+)