Messages in this thread | | | Date | Tue, 17 Feb 2015 10:14:59 +0100 | From | Heinrich Schuchardt <> | Subject | Re: [PATCH 1/1] kernel/fork.c: avoid division by zero |
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On 17.02.2015 08:56, Vladimir Davydov wrote: > On Mon, Feb 16, 2015 at 07:00:44PM +0100, Heinrich Schuchardt wrote: >> diff --git a/kernel/fork.c b/kernel/fork.c >> index cf65139..71e2583 100644 >> --- a/kernel/fork.c >> +++ b/kernel/fork.c >> @@ -273,7 +273,8 @@ void __init fork_init(unsigned long mempages) >> * value: the thread structures can take up at most half >> * of memory. >> */ >> - max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); >> + max_threads = (u64) PAGE_SIZE * (u64) mempages >> + / (u64) THREAD_SIZE / 8UL; > > This won't compile for a 32 bit arch, will it? Should you use div_u64? > > Thanks, > Vladimir > Hello Vladimir,
I compiled the kernel successfully with the patch on a 32bit arm system and Kernel 3.19.0.
Obviously that was good luck. http://gcc.gnu.org/onlinedocs/gccint/Integer-library-routines.html describes that library function __udivti3 might be used on other platforms. And using library functions is not allowable in the kernel.
Thank you for reviewing. I will update the patch.
Best regards
Heinrich
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