Messages in this thread | | | Date | Fri, 8 May 2015 22:59:04 +0200 | Subject | Re: [PATCH] PM / clock_ops: Fix clock error check in __pm_clk_add() | From | Geert Uytterhoeven <> |
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On Fri, May 8, 2015 at 7:19 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > On Fri, May 08, 2015 at 10:47:43AM +0200, Geert Uytterhoeven wrote: >> In the final iteration of commit 245bd6f6af8a62a2 ("PM / clock_ops: Add >> pm_clk_add_clk()"), a refcount increment was added by Grygorii Strashko. >> However, the accompanying IS_ERR() check operates on the wrong clock >> pointer, which is always zero at this point, i.e. not an error. >> This may lead to a NULL pointer dereference later, when __clk_get() >> tries to dereference an error pointer. >> >> Check the passed clock pointer instead to fix this. > > Frankly I would remove the check altogether. Why do we only check for > IS_ERR and not NULL or otherwise validate the pointer? The clk is passed
__clk_get() does the NULL check.
> in and we do not call any API that would return ERR_PTR-encoded value to > us so we shoud lnot even try to handle IS_ERR here. > >> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> Fixes: 245bd6f6af8a62a2 ("PM / clock_ops: Add pm_clk_add_clk()") >> --- >> Note that there are no users of pm_clk_add_clk() in next-20150508, so >> for now no in-tree code is affected. >> --- >> drivers/base/power/clock_ops.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c >> index 7fdd0172605afe1b..c7b0fcebf168cabe 100644 >> --- a/drivers/base/power/clock_ops.c >> +++ b/drivers/base/power/clock_ops.c >> @@ -93,7 +93,7 @@ static int __pm_clk_add(struct device *dev, const char *con_id, >> return -ENOMEM; >> } >> } else { >> - if (IS_ERR(ce->clk) || !__clk_get(clk)) { >> + if (IS_ERR(clk) || !__clk_get(clk)) { >> kfree(ce); >> return -ENOENT; >> } >> -- >> 1.9.1
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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