From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Thu, 19 Jul 2018 20:48:30 -0500
Subject: signal: Properly deliver SIGSEGV from x86 uprobes
Git-commit: 4a63c1ffd384ebdce40aac9c997dab68379137be
Patch-mainline: v4.20-rc1
References: bsc#1110006

For userspace to tell the difference between an random signal
and an exception, the exception must include siginfo information.

Using SEND_SIG_FORCED for SIGSEGV is thus wrong, and it will result in
userspace seeing si_code == SI_USER (like a random signal) instead of
si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.

Therefore replace force_sig_info(SIGSEGV, SEND_SIG_FORCE, current)
with force_sig(SIG_SEGV, current) which gets this right and is shorter
and easier to type.

Fixes: 791eca10107f ("uretprobes/x86: Hijack return address")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/kernel/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -984,7 +984,7 @@ arch_uretprobe_hijack_return_addr(unsign
 		pr_err("uprobe: return address clobbered: pid=%d, %%sp=%#lx, "
 			"%%ip=%#lx\n", current->pid, regs->sp, regs->ip);
 
-		force_sig_info(SIGSEGV, SEND_SIG_FORCED, current);
+		force_sig(SIGSEGV, current);
 	}
 
 	return -1;