Fix missing audit_syscall_exit() on ppc64 sigsuspend exit path

When we leave sigsuspend() directly into a signal handler, we don't want
to go via the normal syscall exit path -- it'll corrupt r4 and r5 which
are supposed to be giving information to the signal handler, and it'll
give us one more single-step SIGTRAP than we need if single-stepping is
in operation.

However, we _should_ be calling audit_syscall_exit(), which would
normally get invoked in that patch. It's not wonderfully pretty, but I
suspect the best answer is just to call it directly...

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/arch/ppc64/kernel/asm-offsets.c b/arch/ppc64/kernel/asm-offsets.c
index abb9e5b5da03b81aa42c88b2ad635f7d1cc00914..6f910fa2746f090eed0cbfd73c4348e10f29e7eb 100644 (file)
--- a/arch/ppc64/kernel/asm-offsets.c
+++ b/arch/ppc64/kernel/asm-offsets.c
@@ -68,6 +68,7 @@ int main(void)
        DEFINE(THREAD_USED_VR, offsetof(struct thread_struct, used_vr));
 #endif /* CONFIG_ALTIVEC */
        DEFINE(MM, offsetof(struct task_struct, mm));
+       DEFINE(AUDITCONTEXT, offsetof(struct task_struct, audit_context));
 
        DEFINE(DCACHEL1LINESIZE, offsetof(struct ppc64_caches, dline_size));
        DEFINE(DCACHEL1LOGLINESIZE, offsetof(struct ppc64_caches, log_dline_size));

diff --git a/arch/ppc64/kernel/entry.S b/arch/ppc64/kernel/entry.S
index b61572eb2a7130d7a46924f8412024b9879286e7..ae5d563ad93a8bff1b4fdbaa9c91b579128dbb00 100644 (file)
--- a/arch/ppc64/kernel/entry.S
+++ b/arch/ppc64/kernel/entry.S
@@ -276,12 +276,20 @@ _GLOBAL(ppc64_rt_sigsuspend)
 _GLOBAL(ppc32_rt_sigsuspend)
        bl      .save_nvgprs
        bl      .sys32_rt_sigsuspend
-       /* If sigsuspend() returns zero, we are going into a signal handler */
 70:    cmpdi   0,r3,0
-       beq     .ret_from_except
-       /* If it returned -EINTR, we need to return via syscall_exit to set
+       /* If it returned an error, we need to return via syscall_exit to set
           the SO bit in cr0 and potentially stop for ptrace. */
-       b       syscall_exit
+       bne     syscall_exit
+       /* If sigsuspend() returns zero, we are going into a signal handler. We
+          may need to call audit_syscall_exit() to mark the exit from sigsuspend() */
+       ld      r3,PACACURRENT(r13)
+       ld      r4,AUDITCONTEXT(r3)
+       cmpdi   0,r4,0
+       beq     .ret_from_except        /* No audit_context: Leave immediately. */
+       li      r4, 2                   /* AUDITSC_FAILURE */
+       li      r5,-4                   /* It's always -EINTR */
+       bl      .audit_syscall_exit
+       b       .ret_from_except
 
 _GLOBAL(ppc_fork)
        bl      .save_nvgprs