Messages in this thread | | | From | Rob Herring <> | Date | Fri, 13 Oct 2017 15:44:06 -0500 | Subject | Re: [PATCH] of: do not leak console options |
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On Fri, Oct 13, 2017 at 2:48 PM, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > On Tue, Oct 3, 2017 at 9:20 AM, Petr Mladek <pmladek@suse.com> wrote: >> On Tue 2017-09-26 15:25:10, Sergey Senozhatsky wrote: >>> Do not strdup() console options. It seems that the only reason for >>> it to be strdup()-ed was a compilation warning: printk, UART and >>> console drivers, for some reason, expect char pointer instead of >>> const char pointer. So we can just pass `of_stdout_options', but >>> need to cast it to char pointer. A better fix would be to change >>> printk, console drivers and UART to accept const char `options'; >>> but that will take time - there are lots of drivers to update. >>> >>> The patch also fixes a possible memory leak: add_preferred_console() >>> can fail, but we don't kfree() options. >>> >>> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> >> >> Of course, it would be better to change add_preferred_console(). >> But it would trigger many other changes. This alternative >> "temporary" change looks safe to me. Feel free to use > > Really? Unless I'm missing something (it's been way too many hours after my > morning coffee), add_preferred_console() just calls __add_preferred_console(), > and the latter doesn't touch the passed string. As passing a "char *" to a > function that excepts a "const char *" is fine, you can just add "const" to > both add_preferred_console() and __add_preferred_console(), and be done with > it.
You've only moved the cast down one level. See the prior discussion[1]. It gets passed to match and setup functions of the console drivers none of which actually modify the string, but it's just a lot of drivers to go fix. Maybe someone wants to write a coccinelle patch.
Anyway, it's in Linus' tree now.
Rob
[1] https://lkml.org/lkml/2017/8/25/784
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