Thread (20 messages) 20 messages, 2 authors, 2018-04-25

Re: [REVIEW][PATCH 05/17] signal/nds32: Use force_sig(SIGILL) in do_revisn

From: Vincent Chen <hidden>
Date: 2018-04-25 12:11:35
Also in: linux-arch, lkml

2018-04-20 9:03 GMT+08:00 Eric W. Biederman [off-list ref]:
quoted hunk ↗ jump to hunk
As originally committed do_revisn would deliver a siginfo for SIGILL
with an si_code composed of random stack contents.  That makes no
sense and is not something userspace can depend on.  So simplify
the code and just use "force_sig(SIG_ILL, current)" instead.

Fixes: 2923f5ea7738 ("nds32: Exception handling")
Cc: Vincent Chen <redacted>
Cc: Greentime Hu <redacted>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: "Eric W. Biederman" <redacted>
---
 arch/nds32/kernel/traps.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index 65961bf91d64..8e9a5b1f6234 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -356,14 +356,11 @@ void do_dispatch_tlb_misc(unsigned long entry, unsigned long addr,

 void do_revinsn(struct pt_regs *regs)
 {
-       siginfo_t si;
        pr_emerg("Reserved Instruction\n");
        show_regs(regs);
        if (!user_mode(regs))
                do_exit(SIGILL);
-       si.si_signo = SIGILL;
-       si.si_errno = 0;
-       force_sig_info(SIGILL, &si, current);
+       force_sig(SIGILL, current);
 }

 #ifdef CONFIG_ALIGNMENT_TRAP
--
2.14.1
You are right we do not store any valuable information in sigingo_t now.
However, We hope more information can be recorded by force_sig_fault()
as below instead of calling force_sig() directly.

-        force_sig(SIGILL, current);
+        force_sig_fault(SIGILL, ILL_ILLTRP,
+                        (void __user *)instruction_pointer(regs), current);

Thanks

Vincent Chen
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