On Thu, Jan 11, 2018 at 06:59:32PM -0600, Eric W. Biederman wrote:
> While reviewing the signal sending on openrisc the do_unaligned_access
> function stood out because it is obviously wrong. A comment about an
> si_code set above when actually si_code is never set. Leading to a
> random si_code being sent to userspace in the event of an unaligned
> access.
>
> Looking further SIGBUS BUS_ADRALN is the proper pair of signal and
> si_code to send for an unaligned access. That is what other
> architectures do and what is required by posix.
>
> Given that do_unaligned_access is broken in a way that no one can be
> relying on it on openrisc fix the code to just do the right thing.
Thanks, this looks good to me.
Acked-by: Stafford Horne <shorne@xxxxxxxxx>
I see you have a series of related issues, so I guess you want to get them
merged together. Let me know if I should put this patch onto my queue
seperately.
Trivia: this looks to have been copied from the mm page fault handling code,
hence the strange comment.
$ grep -r "info.si_code has been set above" arch/
arch/cris/mm/fault.c: /* info.si_code has been set above */
arch/m32r/mm/fault.c: /* info.si_code has been set above */
arch/mn10300/mm/fault.c: /* info.si_code has been set above */
arch/openrisc/mm/fault.c: /* info.si_code has been set above */
arch/openrisc/kernel/traps.c: /* info.si_code has been set above */
arch/arc/mm/fault.c: /* info.si_code has been set above */
arch/xtensa/mm/fault.c: /* info.si_code has been set above */
arch/mips/mm/fault.c: /* info.si_code has been set above */
arch/score/mm/fault.c: /* info.si_code has been set above */
arch/frv/mm/fault.c: /* info.si_code has been set above */
-Stafford
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 769a8a96229e ("OpenRISC: Traps")
> Cc: Jonas Bonn <jonas@xxxxxxxxxxxx>
> Cc: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
> Cc: Stafford Horne <shorne@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: openrisc@xxxxxxxxxxxxxxxxxxxx
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> ---
> arch/openrisc/kernel/traps.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
> index 4085d72fa5ae..9e38dc66c9e4 100644
> --- a/arch/openrisc/kernel/traps.c
> +++ b/arch/openrisc/kernel/traps.c
> @@ -266,12 +266,12 @@ asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
> siginfo_t info;
>
> if (user_mode(regs)) {
> - /* Send a SIGSEGV */
> - info.si_signo = SIGSEGV;
> + /* Send a SIGBUS */
> + info.si_signo = SIGBUS;
> info.si_errno = 0;
> - /* info.si_code has been set above */
> - info.si_addr = (void *)address;
> - force_sig_info(SIGSEGV, &info, current);
> + info.si_code = BUS_ADRALN;
> + info.si_addr = (void __user *)address;
> + force_sig_info(SIGBUS, &info, current);
> } else {
> printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
> show_registers(regs);
> --
> 2.14.1
>