Messages in this thread | | | Date | Sun, 4 Jul 1999 10:11:07 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [patch] fix for OOM deadlock in swap_in (2.2.10) [Re: [test program] for OOM situations ] |
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On Sun, 4 Jul 1999, Rik van Riel wrote:
> On Sat, 3 Jul 1999, Andrea Arcangeli wrote: > > > +void oom(void) > > { > ... > > + force_sig(SIGKILL, current); > > > I would like to get some feedback about the patch. Thanks :). > > I'm curious why you haven't yet included my process > selection algoritm. I know it can select a blocked > or otherwise unkillable process the way the code is > in right now, but a workaround for that can be made > in about 5 minutes.
Andreas patch has a much more serious problem: it changes accepted UNIX semantics. Try this before and after the patch:
#include <unistd.h> #include <fcntl.h> #include <sys/mman.h>
#define PAGE_SIZE 4096
int main(int argc, char **argv) { int fd; char * map;
fd = open("/tmp/duh", O_RDWR | O_CREAT, 0666); if (fd < 0) exit(1); ftruncate(fd, PAGE_SIZE); map = mmap(NULL, PAGE_SIZE*2, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); *(volatile char *)(map+PAGE_SIZE); return 0; }
and see the difference..
I have tried to fix this _correctly_ in 2.3.10-pre2. That fix could be back-ported to 2.2.x, but Andreas patch really is not acceptable.
And Andrea, I told you this once already in private email. I told you why. Why don't you listen? "Fixing" a bug badly is worse than leaving it as a known bug.
Linus
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