4.4-stable review patch. If anyone has any objections, please let me know.
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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);