Commit 17888225 authored by David Woodhouse's avatar David Woodhouse
Browse files

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: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 3c789a19

arch/ppc64/kernel/asm-offsets.c

+1 −0
Original line number Diff line number Diff line
@@ -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));

arch/ppc64/kernel/entry.S

+12 −4
Original line number Diff line number Diff line
@@ -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

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