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authorAlistair Popple <alistair@popple.id.au>2013-04-15 05:44:14 +0400
committerStephen Rothwell <sfr@canb.auug.org.au>2013-04-15 11:29:45 +0400
commit05e38e5d5d437c762c79428ae8434632a8ca2c5e (patch)
tree24822ddcb81ca867d1b67106e74f75777dab1978 /arch/powerpc
parentf110c0c1926028a233830c6166e4d40314420823 (diff)
downloadlinux-05e38e5d5d437c762c79428ae8434632a8ca2c5e.tar.xz
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 <haren@linux.vnet.ibm.com> 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 <alistair@popple.id.au> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/entry_64.S2
1 files changed, 1 insertions, 1 deletions
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