summaryrefslogtreecommitdiff
path: root/arch/powerpc/oprofile/backtrace.c
diff options
context:
space:
mode:
authorJiang Lu <lu.jiang@windriver.com>2014-11-21 11:23:19 +0800
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-12-02 14:10:08 +1100
commit0de3b56b137e92afa6a4581a0bb51633159180d6 (patch)
tree3c4a6398f1064656b95e6b5c9dc807b7bea6e9ed /arch/powerpc/oprofile/backtrace.c
parent0ec2698fe1c451606c16e21dbfbd29efce694668 (diff)
downloadlinux-sh-0de3b56b137e92afa6a4581a0bb51633159180d6.tar.gz
powerpc/oprofile: Disable pagefaults during user stack read
A page fault occurred during reading user stack in oprofile backtrace would lead following calltrace: WARNING: at linux/kernel/smp.c:210 Modules linked in: CPU: 5 PID: 736 Comm: sh Tainted: G W 3.14.23-WR7.0.0.0_standard #1 task: c0000000f6208bc0 ti: c00000007c72c000 task.ti: c00000007c72c000 NIP: c0000000000ed6e4 LR: c0000000000ed5b8 CTR: 0000000000000000 REGS: c00000007c72f050 TRAP: 0700 Tainted: G W (3.14.23-WR7.0.0 tandard) MSR: 0000000080021000 <CE,ME> CR: 48222482 XER: 00000000 SOFTE: 0 GPR00: c0000000000ed5b8 c00000007c72f2d0 c0000000010aa048 0000000000000005 GPR04: c000000000fdb820 c00000007c72f410 0000000000000001 0000000000000005 GPR08: c0000000010b5768 c000000000f8a048 0000000000000001 0000000000000000 GPR12: 0000000048222482 c00000000fffe580 0000000022222222 0000000010129664 GPR16: 0000000010143cc0 0000000000000000 0000000044444444 0000000000000000 GPR20: c00000007c7221d8 c0000000f638e3c8 000003f15a20120d 0000000000000001 GPR24: 000000005a20120d c00000007c722000 c00000007cdedda8 00003fffef23b160 GPR28: 0000000000000001 c00000007c72f410 c000000000fdb820 0000000000000006 NIP [c0000000000ed6e4] .smp_call_function_single+0x18c/0x248 LR [c0000000000ed5b8] .smp_call_function_single+0x60/0x248 Call Trace: [c00000007c72f2d0] [c0000000000ed5b8] .smp_call_function_single+0x60/0x248 (unreliable) [c00000007c72f3a0] [c000000000030810] .__flush_tlb_page+0x164/0x1b0 [c00000007c72f460] [c00000000002e054] .ptep_set_access_flags+0xb8/0x168 [c00000007c72f500] [c0000000001ad3d8] .handle_mm_fault+0x4a8/0xbac [c00000007c72f5e0] [c000000000bb3238] .do_page_fault+0x3b8/0x868 [c00000007c72f810] [c00000000001e1d0] storage_fault_common+0x20/0x44 Exception: 301 at .__copy_tofrom_user_base+0x54/0x5b0 LR = .op_powerpc_backtrace+0x190/0x20c [c00000007c72fb00] [c000000000a2ec34] .op_powerpc_backtrace+0x204/0x20c (unreliable) [c00000007c72fbc0] [c000000000a2b5fc] .oprofile_add_ext_sample+0xe8/0x118 [c00000007c72fc70] [c000000000a2eee0] .fsl_emb_handle_interrupt+0x20c/0x27c [c00000007c72fd30] [c000000000a2e440] .op_handle_interrupt+0x44/0x58 [c00000007c72fdb0] [c000000000016d68] .performance_monitor_exception+0x74/0x90 [c00000007c72fe30] [c00000000001d8b4] exc_0x260_common+0xfc/0x100 performance_monitor_exception() is executed in a context with interrupt disabled and preemption enabled. When there is a user space page fault happened, do_page_fault() invoke in_atomic() to decide whether kernel should handle such page fault. in_atomic() only check preempt_count. So need call pagefault_disable() to disable preemption before reading user stack. Signed-off-by: Jiang Lu <lu.jiang@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/oprofile/backtrace.c')
-rw-r--r--arch/powerpc/oprofile/backtrace.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
index 6adf55fa5d88..ecc66d5f02c9 100644
--- a/arch/powerpc/oprofile/backtrace.c
+++ b/arch/powerpc/oprofile/backtrace.c
@@ -10,7 +10,7 @@
#include <linux/oprofile.h>
#include <linux/sched.h>
#include <asm/processor.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
#include <asm/compat.h>
#include <asm/oprofile_impl.h>
@@ -105,6 +105,7 @@ void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
first_frame = 0;
}
} else {
+ pagefault_disable();
#ifdef CONFIG_PPC64
if (!is_32bit_task()) {
while (depth--) {
@@ -113,7 +114,7 @@ void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
break;
first_frame = 0;
}
-
+ pagefault_enable();
return;
}
#endif
@@ -124,5 +125,6 @@ void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
break;
first_frame = 0;
}
+ pagefault_enable();
}
}