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@gmail.com
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@vger.kernel.org Fixes: 769a8a96229e ("OpenRISC: Traps") Cc: Jonas Bonn jonas@southpole.se Cc: Stefan Kristiansson stefan.kristiansson@saunalahti.fi Cc: Stafford Horne shorne@gmail.com Cc: Arnd Bergmann arnd@arndb.de Cc: openrisc@lists.librecores.org Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com
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_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);-- 2.14.1