From: Eric W. Biederman ebiederm@xmission.com
commit d76cac67db40c172791ce07948367b96a758e45b upstream.
I don't think this is userspace visible but SIGKILL does not have any si_codes that use the fault member of the siginfo union. Correct this the simple way and call force_sig instead of force_sig_fault when the signal is SIGKILL.
The two know places where synchronous SIGKILL are generated are do_bad_area and fpsimd_save. The call paths to force_sig_fault are: do_bad_area arm64_force_sig_fault force_sig_fault force_signal_inject arm64_notify_die arm64_force_sig_fault force_sig_fault
Which means correcting this in arm64_force_sig_fault is enough to ensure the arm64 code is not misusing the generic code, which could lead to maintenance problems later.
Cc: stable@vger.kernel.org Cc: Dave Martin Dave.Martin@arm.com Cc: James Morse james.morse@arm.com Cc: Will Deacon will.deacon@arm.com Fixes: af40ff687bc9 ("arm64: signal: Ensure si_code is valid for all fault signals") Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/kernel/traps.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -256,7 +256,10 @@ void arm64_force_sig_fault(int signo, in const char *str) { arm64_show_signal(signo, str); - force_sig_fault(signo, code, addr, current); + if (signo == SIGKILL) + force_sig(SIGKILL, current); + else + force_sig_fault(signo, code, addr, current); }
void arm64_force_sig_mceerr(int code, void __user *addr, short lsb,