Fix syscall_get_set_args_cb() to decode user-stack correctly in case of
syscall() which allocates locals in user-stack. If locals (cfm.sol) exist
on the stack, we have to skip it for getting real systemcall arguments.
And also, fix the number of getting arguments which must be less than
(nr outputs - args->i) instead of nr outputs, because args->i is the
indent number (this means, syscall_get_set_args_cb() get/set arguments
from (i)th to (i+n)th.)
Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: Anil S Keshavamurthy <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: David Smith <[email protected]>
---
arch/ia64/kernel/ptrace.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
Index: 2.6-rc/arch/ia64/kernel/ptrace.c
===================================================================
--- 2.6-rc.orig/arch/ia64/kernel/ptrace.c
+++ 2.6-rc/arch/ia64/kernel/ptrace.c
@@ -2189,6 +2189,10 @@ struct syscall_get_set_args {
int rw;
};
+#define CFM_SOF(cfm) ((cfm) & 0x7f) /* Size of frame */
+#define CFM_SOL(cfm) (((cfm) >> 7) & 0x7f) /* Size of locals */
+#define CFM_OUT(cfm) (CFM_SOF(cfm) - CFM_SOL(cfm)) /* Size of outputs */
+
static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
{
struct syscall_get_set_args *args = data;
@@ -2205,15 +2209,18 @@ static void syscall_get_set_args_cb(stru
count = 0;
if (in_syscall(pt))
- count = min_t(int, args->n, cfm & 0x7f);
+ /* args->i + args->n must be less equal than nr outputs */
+ count = min_t(int, args->n, CFM_OUT(cfm) - args->i);
for (i = 0; i < count; i++) {
+ /* Skips dirties and locals */
if (args->rw)
- *ia64_rse_skip_regs(krbs, ndirty + i + args->i) =
+ *ia64_rse_skip_regs(krbs,
+ ndirty + CFM_SOL(cfm) + args->i + i) =
args->args[i];
else
args->args[i] = *ia64_rse_skip_regs(krbs,
- ndirty + i + args->i);
+ ndirty + CFM_SOL(cfm) + args->i + i);
}
if (!args->rw) {
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: [email protected]
Hi,
Actually, this patch is not only for utrace, but also fixing /proc/pid/syscall.
I made a small program which reads /proc/pid/syscall via both of read() and syscall().
Without this patch:
---
read() read: 1026 0x3 0x60000fffffcb75e8 0x100 0x60000fffffcb7700 0x0 0x20000000000b03f0 0x600007ffffcbc020
0xa000000000010721
syscall() read: 1026 0x402 0x3 0x60000fffffcb75e8 0x100 0x2a8 0x0 0x600007ffffcbc048 0x2000000000209730
---
You can see "0x402"(1026) appeared at syscall() read result.
With this patch:
---
read() read: 1026 0x3 0x60000fffff8a35c8 0x100 0x60000fffff8a36e0 0x0 0x20000000000b03f0 0x600007ffff8a8020
0xa000000000010721
syscall() read: 1026 0x3 0x60000fffff8a35c8 0x100 0x2a8 0x0 0x4 0x600007ffff8a8048 0x2000000000209730
---
Here, you can see that "0x402" disappeared from syscall() case.
Thank you,
Masami Hiramatsu wrote:
> Fix syscall_get_set_args_cb() to decode user-stack correctly in case of
> syscall() which allocates locals in user-stack. If locals (cfm.sol) exist
> on the stack, we have to skip it for getting real systemcall arguments.
>
> And also, fix the number of getting arguments which must be less than
> (nr outputs - args->i) instead of nr outputs, because args->i is the
> indent number (this means, syscall_get_set_args_cb() get/set arguments
> from (i)th to (i+n)th.)
>
> Signed-off-by: Masami Hiramatsu <[email protected]>
> Cc: Anil S Keshavamurthy <[email protected]>
> Cc: Roland McGrath <[email protected]>
> Cc: David Smith <[email protected]>
> ---
> arch/ia64/kernel/ptrace.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> Index: 2.6-rc/arch/ia64/kernel/ptrace.c
> ===================================================================
> --- 2.6-rc.orig/arch/ia64/kernel/ptrace.c
> +++ 2.6-rc/arch/ia64/kernel/ptrace.c
> @@ -2189,6 +2189,10 @@ struct syscall_get_set_args {
> int rw;
> };
>
> +#define CFM_SOF(cfm) ((cfm) & 0x7f) /* Size of frame */
> +#define CFM_SOL(cfm) (((cfm) >> 7) & 0x7f) /* Size of locals */
> +#define CFM_OUT(cfm) (CFM_SOF(cfm) - CFM_SOL(cfm)) /* Size of outputs */
> +
> static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
> {
> struct syscall_get_set_args *args = data;
> @@ -2205,15 +2209,18 @@ static void syscall_get_set_args_cb(stru
>
> count = 0;
> if (in_syscall(pt))
> - count = min_t(int, args->n, cfm & 0x7f);
> + /* args->i + args->n must be less equal than nr outputs */
> + count = min_t(int, args->n, CFM_OUT(cfm) - args->i);
>
> for (i = 0; i < count; i++) {
> + /* Skips dirties and locals */
> if (args->rw)
> - *ia64_rse_skip_regs(krbs, ndirty + i + args->i) =
> + *ia64_rse_skip_regs(krbs,
> + ndirty + CFM_SOL(cfm) + args->i + i) =
> args->args[i];
> else
> args->args[i] = *ia64_rse_skip_regs(krbs,
> - ndirty + i + args->i);
> + ndirty + CFM_SOL(cfm) + args->i + i);
> }
>
> if (!args->rw) {
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: [email protected]