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Re: [lkcd-devel] Another problem with lcrash command task
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From: Piet/Pete D. <pi...@sg...> - 2002-04-28 09:26:17
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On Fri, Apr 26, 2002 at 08:15:14PM +0530, Deepak Kumar Gupta, Noida wrote:
Could you regenerate your patch, there are added new lines <NL> in the
patch file and patch -p1 </tmp/patch is failing. I fixed one and just hit
another here at line 53, and see another at line 55.
Considering that late date and that it hasn't been tested on ia64 I suggest
we don't add it unless I can verify that it's ok.
I just check lkcdutils and as of now ia64 appears to be fine.
If you send another patch I can try it tomarrow (Sunday) and if it checks out then
it's ok with me. Since it's a fix for when the user makes a mistake I don't think
it's that important to get it in without testing it on ia64 first.
-piet
45 +/* Function Name: task_validate
46 + *
47 + * Description: The function compares the given address with addresses of
48 + * available active tasks.
49 + *
50 + * Input : Address of task to be validated.
51 + *
52 + * Output : 1 if the input address matches with address of any of
53 active task.
54 + * : 0 if input address doesn't match with address of any of
55 active task
56 + * OR any error occurred.
57 + */
> Hello List
>
> First of all thanks to Steve for precious feedback on previous patch.
>
> I am using lkcdutils-4.1-pre2 with lkcd-4.1-pre2.patch for kernel 2.4.17 and
> using it for i386 architecture. I have observed another problem with lcrash
> command task. The problem is as follows:-
>
> PROBLEM DESCRIPTION
> ====================
> ___snip____
>
> >> task
> ADDR UID PID PPID STATE FLAGS CPU NAME
> ============================================================================
> ===
> 0xc0302000 0 0 0 0 0x100 0 swapper
> 0xc2406000 0 1124 1 1 0x40 - kdeinit
> . . . . . . .
> . . . . . . .
> . . . . . . .
> 0xc2434000 0 1125 1124 1 0x100 - cat
> 0xc254c000 0 1127 1 1 0x40 - alarmd
> 0xc2f82000 0 1128 1110 1 0x140 - kdeinit
> 0xc1f1a000 0 1129 1128 1 0x100 - bash
> 0xc1a98000 0 2229 1128 1 0x100 - bash
> 0xc7a84000 0 2292 933 1 0x100 - bash
> ============================================================================
> ===
> 48 active task structs found
> >>
> >> task c2f82000 c1f1a300 c1f1a045 c7a84000 /* (__HERE ADDRESSES c1f1a300
> AND c1f1a045 ARE NOT ACTUAL TASK ADDRESS__) */
> ADDR UID PID PPID STATE FLAGS CPU NAME
> ============================================================================
> ===
> 0xc2f82000 0 1128 1110 1 0x140 - kdeinit
> 0xc1f1a300 0 0 4294967295 4294967295 0 -
> 0xc1f1a045 0 3233935776 4294967295 697 0xc1a980 16777216
> 0xc7a84000 0 2292 933 1 0x100 - bash
> ============================================================================
> ===
> 4 active task structs found
> >>
> ___snip____
>
> That is if task command is executed for addresses which are not actually
> start address of tasks then also it prints the values of parameters like
> PID, PPID, STATE, FLAGS, CPU and NAME and consider them as active tasks. The
> values printed by command are meaningless.
>
> In my opinion this is bug, but if experts think that this is OK then please
> ignore rest of mail and update me.
>
> PROBLEM ANALYSIS
> =================
> After looking at task_cmd function of lkcdutils-4.1/lcrash/cmds/cmd_task.c
> it is observed that the addresses ( either given by user or obtained by
> kl_pid_to_task ) are passed to print_task_struct without checking that
> whether the address is actually a task OR not.
>
> PROBLEM SOLUTION
> =================
> The address passed to print_task_struct should be compare with actual task
> addresses.
>
> PATCH
> ======
> For solving the problem, I have borrowed part of code from function
> print_active_tasks().
>
> Initially I have thought to include the part of code in cmd_task function
> itself. But later I decided to have a separate function.
>
> This patch is also removing one unused variable from function
> ldcmds_complete(command_t *cmd) of lcrash/cmds/cmd_ldcmds.c
>
> Following is the patch:
>
>
> diff -Naur lkcdutils-4.1/lcrash/cmds/cmd_ldcmds.c
> lkcdutils-4.1_mod/lcrash/cmds/cmd_ldcmds.c
> --- lkcdutils-4.1/lcrash/cmds/cmd_ldcmds.c Wed Mar 20 16:57:27 2002
> +++ lkcdutils-4.1_mod/lcrash/cmds/cmd_ldcmds.c Fri Apr 26 19:28:15 2002
> @@ -68,8 +68,6 @@
> char *
> ldcmds_complete(command_t *cmd)
> {
> - char *ret;
> -
> /* complete standard options (for example, -w option) arguments
> */
> if ((cmd->nargs == 1)) {
> diff -Naur lkcdutils-4.1/lcrash/cmds/cmd_task.c
> lkcdutils-4.1_mod/lcrash/cmds/cmd_task.c
> --- lkcdutils-4.1/lcrash/cmds/cmd_task.c Wed Mar 20 16:57:27 2002
> +++ lkcdutils-4.1_mod/lcrash/cmds/cmd_task.c Fri Apr 26 19:44:51 2002
> @@ -3,6 +3,7 @@
> */
> #include <lcrash.h>
>
> +int task_validate(kaddr_t);
> /*
> * task_cmd() -- Run the 'task' command.
> */
> @@ -42,9 +43,11 @@
> if (mode == 1) {
> task = kl_pid_to_task(task);
> }
> - print_task_struct(task, tsp,
> + if (task_validate(task)) {
> + print_task_struct(task, tsp,
> cmd->flags, cmd->ofp);
> - task_cnt++;
> + task_cnt++;
> + }
> } else {
> fprintf(KL_ERRORFP, "Invalid task : "
> "0x%lx\n", (long unsigned int
> )task);
> @@ -112,3 +115,63 @@
> task_usage(cmd);
> return(DRAW_NEW_ENTIRE_LINE);
> }
> +
> +/* Function Name: task_validate
> + *
> + * Description: The function compares the given address with addresses of
> + * available active tasks.
> + *
> + * Input : Address of task to be validated.
> + *
> + * Output : 1 if the input address matches with address of any of
> active task.
> + * : 0 if input address doesn't match with address of any of
> active task
> + * OR any error occurred.
> + */
> +
> +int
> +task_validate(kaddr_t task)
> +{
> + kaddr_t addr, first_task;
> + syment_t *sp;
> +#if (ARCH == ia64)
> + kaddr_t p1, p2;
> +#endif
> + void *tsp;
> + if (LINUX_2_2_X(KL_LINUX_RELEASE)) {
> + if (!(sp = kl_lkup_symname("init_task_union"))) {
> + return(0);
> + }
> + first_task = sp->s_addr;
> + } else {
> + if (!(sp = kl_lkup_symname("init_tasks"))) {
> + return(0);
> + }
> + GET_BLOCK(sp->s_addr, sizeof(kaddr_t), &first_task);
> + }
> + addr = first_task;
> + if (!(tsp = kl_alloc_block(TASK_STRUCT_SZ, K_TEMP))) {
> + return(0);
> + }
> + do {
> + if (kl_get_task_struct(addr, 2, tsp)) {
> + return(0);
> + }
> + if (addr == task) {
> + return(1);
> + }
> + addr = kl_kaddr(tsp, "task_struct", "next_task");
> +
> +#if (ARCH == ia64)
> + if (kl_virtop(addr, NULL, &p1)) {
> + break;
> + }
> + if (kl_virtop(first_task, NULL, &p2)) {
> + break;
> + }
> + } while (p1 != p2);
> +#else
> + } while (addr != first_task);
> +#endif
> + kl_free_block(tsp);
> + return(0);
> +}
>
> AFTER APPLYING THE PATCH
> =========================
> >> task c2f82000 c1f1a300 c1f1a045 c7a84000
> ADDR UID PID PPID STATE FLAGS CPU NAME
> ============================================================================
> ===
> 0xc2f82000 0 1128 1110 1 0x140 - kdeinit
> 0xc7a84000 0 2292 933 1 0x100 - bash
> ============================================================================
> ===
> 2 active task structs found
> >>
>
> TESTING
> =========
> I have tested it only for i386 platform. For ia64 platform I have not
> tested, but hope it should work.
>
> I request the experts to have a look at patch. Please provide feedback and
> cc the reply to me also.
>
> Looking for precious comments
> Thanks
> Deepak.
>
>
>
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