This is a note to let you know that I've just added the patch titled
signal/openrisc: Fix do_unaligned_access to send the proper signal
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: signal-openrisc-fix-do_unaligned_access-to-send-the-proper-signal.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 500d58300571b6602341b041f97c082a461ef994 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" ebiederm@xmission.com Date: Tue, 1 Aug 2017 04:16:47 -0500 Subject: signal/openrisc: Fix do_unaligned_access to send the proper signal
From: Eric W. Biederman ebiederm@xmission.com
commit 500d58300571b6602341b041f97c082a461ef994 upstream.
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.
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 Acked-by: Stafford Horne shorne@gmail.com Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/openrisc/kernel/traps.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/arch/openrisc/kernel/traps.c +++ b/arch/openrisc/kernel/traps.c @@ -302,12 +302,12 @@ asmlinkage void do_unaligned_access(stru 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);
Patches currently in stable-queue which might be from ebiederm@xmission.com are
queue-4.9/signal-openrisc-fix-do_unaligned_access-to-send-the-proper-signal.patch queue-4.9/signal-sh-ensure-si_signo-is-initialized-in-do_divide_error.patch