Re: [PATCH] mm/slub: fix to return errno if kmalloc() fails

[Matthew Wilcox]

On Thu, Sep 08, 2022 at 11:25:08PM +0200, Vlastimil Babka (SUSE) wrote:
> > I tend to agree with you. A mount operation shouldn’t panic the
> > kernel.
> 
> Hmm kmalloc(64) shouldn't normally due that due to the the underlying page
> allocation falling into the "too small to fail" category, wonder if
> syzkaller was doing anything special here?

Here's the repro:

https://syzkaller.appspot.com/x/repro.c?x=17cd7fa3080000

you can see it does:

  fd = open("/proc/thread-self/fail-nth", O_RDWR);
  if (fd == -1)
    exit(1);
  char buf[16];
  sprintf(buf, "%d", nth);
  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))

so this is the kind of stupid nitpicky bug that we shouldn't be
reporting, let alone fixing, IMO.