[PATCH] arm64: ptrace: fix empty registers set in prstatus of aarch32 process core

Victor Kamensky victor.kamensky at linaro.org
Tue Jun 3 11:21:30 PDT 2014


Currently core file of aarch32 process prstatus note has empty
registers set. As result aarch32 core files create by V8 kernel are
not very useful.

It happens because compat_gpr_get and compat_gpr_set functions can
copy registers values to/from either kbuf or ubuf. ELF core file
collection function fill_thread_core_info calls compat_gpr_get
with kbuf set and ubuf set to 0. But current compat_gpr_get and
compat_gpr_set function handle copy to/from only ubuf case.

Fix is to handle kbuf and ubuf as two separate cases in similar
way as other functions like user_regset_copyout, user_regset_copyin do.

Signed-off-by: Victor Kamensky <victor.kamensky at linaro.org>
Acked-by: Will Deacon <will.deacon at arm.com>
Cc: stable at vger.kernel.org
Cc: Catalin Marinas <catalin.marinas at arm.com>
---
 arch/arm64/kernel/ptrace.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 6a8928b..9c9c2b9 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -650,11 +650,16 @@ static int compat_gpr_get(struct task_struct *target,
 			reg = task_pt_regs(target)->regs[idx];
 		}
 
-		ret = copy_to_user(ubuf, &reg, sizeof(reg));
-		if (ret)
-			break;
-
-		ubuf += sizeof(reg);
+		if (kbuf) {
+			memcpy(kbuf, &reg, sizeof(reg));
+			kbuf += sizeof(reg);
+		} else {
+			ret = copy_to_user(ubuf, &reg, sizeof(reg));
+			if (ret)
+				break;
+
+			ubuf += sizeof(reg);
+		}
 	}
 
 	return ret;
@@ -684,11 +689,16 @@ static int compat_gpr_set(struct task_struct *target,
 		unsigned int idx = start + i;
 		compat_ulong_t reg;
 
-		ret = copy_from_user(&reg, ubuf, sizeof(reg));
-		if (ret)
-			return ret;
+		if (kbuf) {
+			memcpy(&reg, kbuf, sizeof(reg));
+			kbuf += sizeof(reg);
+		} else {
+			ret = copy_from_user(&reg, ubuf, sizeof(reg));
+			if (ret)
+				return ret;
 
-		ubuf += sizeof(reg);
+			ubuf += sizeof(reg);
+		}
 
 		switch (idx) {
 		case 15:
-- 
1.8.1.4




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