Commit 6471c3d1 authored Aug 01, 2017 by Eric W. Biederman Committed by Greg Kroah-Hartman Feb 16, 2018

signal/openrisc: Fix do_unaligned_access to send the proper signal



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: 769a8a96 ("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>

parent 32a3eda0

arch/openrisc/kernel/traps.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -302,12 +302,12 @@ 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);