Subject: Re: [xmon PATCH 1/1] RFC: Add xmon command to dump process/task similar to ps(1)

From: Douglas Miller <[email-masked]>
Date: Tue, 10 Nov 2015 10:50:25 -0600

Sorry, rookie mistake: last minute changes without checking compile.

Here's is the corrected patch.

On 11/10/2015 09:31 AM, Douglas Miller wrote:
> RFC: Not sure if I need locking when accessing task structs from xmon. 
> Please comment.
>
> I found this new xmon command indispensable while debugging a KDUMP 
> problem. It dumps some task information similar to the ps(1) command, 
> plus includes the kernel stack pointer for use with "t" traceback 
> command. In the case of KDUMP on PKVM, it was running single-CPU so 
> locking issues would likely not have shown up. Certainly if xmon runs 
> in an environment where some CPUs are still running tasks, this 
> information can be very fleeting.
>
> Let me know what else needs to be done to make this patch ready.
>
> Thanks,
> Doug
>
>
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> Linuxppc-dev mailing list
> [email-masked]
> https://lists.ozlabs.org/listinfo/linuxppc-dev

>>From 18a3fff40f84973639ddf1e519a5976b90cec33f Mon Sep 17 00:00:00 2001
From: Douglas Miller <[email-masked]>
Date: Thu, 5 Nov 2015 07:55:33 -0600
Subject: [PATCH] Add xmon command to dump process/task similar to ps(1)

---
 arch/powerpc/xmon/xmon.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 13c6e20..72f0404 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -149,6 +149,7 @@ static int  cpu_cmd(void);
 static void csum(void);
 static void bootcmds(void);
 static void proccall(void);
+static void proclist(void);
 void dump_segments(void);
 static void symbol_lookup(void);
 static void xmon_show_stack(unsigned long sp, unsigned long lr,
@@ -228,6 +229,7 @@ Commands:\n\
   mz	zero a block of memory\n\
   mi	show information about memory allocation\n\
   p 	call a procedure\n\
+  P 	list processes/tasks\n\
   r	print registers\n\
   s	single step\n"
 #ifdef CONFIG_SPU_BASE
@@ -947,6 +949,9 @@ cmds(struct pt_regs *excp)
 		case 'p':
 			proccall();
 			break;
+		case 'P':
+			proclist();
+			break;
 #ifdef CONFIG_PPC_STD_MMU
 		case 'u':
 			dump_segments();
@@ -2450,6 +2455,39 @@ memzcan(void)
 		printf("%.8x\n", a - mskip);
 }
 
+static void procshow(struct task_struct *tsk)
+{
+	char state;
+	state = (tsk->state == 0) ? 'R' :
+		(tsk->state < 0) ? 'U' :
+		(tsk->state & TASK_UNINTERRUPTIBLE) ? 'D' :
+		(tsk->state & TASK_STOPPED) ? 'T' :
+		(tsk->state & TASK_TRACED) ? 'C' :
+		(tsk->exit_state & EXIT_ZOMBIE) ? 'Z' :
+		(tsk->exit_state & EXIT_DEAD) ? 'E' :
+		(tsk->state & TASK_INTERRUPTIBLE) ? 'S' : '?';
+
+	printf("%p %016lx %6d %6d %c %2d %s\n", tsk,
+		tsk->thread.ksp,
+		tsk->pid, tsk->parent->pid,
+		state, task_thread_info(tsk)->cpu,
+		tsk->comm);
+}
+
+static void proclist(void)
+{
+	unsigned long tskv;
+	struct task_struct *tsk;
+
+	if (scanhex(&tskv)) {
+		procshow((struct task_struct *)tskv);
+	} else {
+		for_each_process(tsk) {
+			procshow(tsk);
+		}
+	}
+}
+
 static void proccall(void)
 {
 	unsigned long args[8];
-- 
1.7.1