On Apr 09 2019, Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
Now the question I'm asking myself is: why does pagefault_disable() not
suppress the bus error here:
long __probe_kernel_read(void *dst, const void *src, size_t size)
{
long ret;
mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
pagefault_disable();
current->kernel_uaccess_faults_ok++;
ret = __copy_from_user_inatomic(dst,
(__force const void __user *)src, size);
current->kernel_uaccess_faults_ok--;
pagefault_enable();
set_fs(old_fs);
return ret ? -EFAULT : 0;
}
If I read the m68k mm/fault.c code right, we should see user space take a
SIGBUS, not SIGSEGV.
Since this is from KERNEL_DS it is a kernel space access.
Andreas.
--
Andreas Schwab, schwab@xxxxxxxxxxxxxx
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