From: Alistair Popple Date: Mon, 15 Apr 2013 01:44:14 +0000 (+1000) Subject: powerpc: Fix audit crash due to save/restore PPR changes X-Git-Tag: v3.9-rc8~24^2~1 X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=05e38e5d5d437c762c79428ae8434632a8ca2c5e powerpc: Fix audit crash due to save/restore PPR changes The current mainline crashes when hitting userspace with the following: kernel BUG at kernel/auditsc.c:1769! cpu 0x1: Vector: 700 (Program Check) at [c000000023883a60] pc: c0000000001047a8: .__audit_syscall_entry+0x38/0x130 lr: c00000000000ed64: .do_syscall_trace_enter+0xc4/0x270 sp: c000000023883ce0 msr: 8000000000029032 current = 0xc000000023800000 paca = 0xc00000000f080380 softe: 0 irq_happened: 0x01 pid = 1629, comm = start_udev kernel BUG at kernel/auditsc.c:1769! enter ? for help [c000000023883d80] c00000000000ed64 .do_syscall_trace_enter+0xc4/0x270 [c000000023883e30] c000000000009b08 syscall_dotrace+0xc/0x38 --- Exception: c00 (System Call) at 0000008010ec50dc Bisecting found the following patch caused it: commit 44e9309f1f357794b7ae93d5f3e3e6f11d2b8a7f Author: Haren Myneni powerpc: Implement PPR save/restore It was found this patch corrupted r9 when calling SET_DEFAULT_THREAD_PPR() Using r10 as a scratch register instead of r9 solved the problem. Signed-off-by: Alistair Popple Acked-by: Michael Neuling Signed-off-by: Stephen Rothwell --- diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 256c5bf0adb7..3acb1a076d3f 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -304,7 +304,7 @@ syscall_exit_work: subi r12,r12,TI_FLAGS 4: /* Anything else left to do? */ - SET_DEFAULT_THREAD_PPR(r3, r9) /* Set thread.ppr = 3 */ + SET_DEFAULT_THREAD_PPR(r3, r10) /* Set thread.ppr = 3 */ andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP) beq .ret_from_except_lite