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authorDouglas Anderson <dianders@chromium.org>2019-11-09 11:16:43 -0800
committerDaniel Thompson <daniel.thompson@linaro.org>2020-01-31 17:34:00 +0000
commit9441d5f6b77770ee388884f04b14a99b028a15e6 (patch)
tree2061f7a95b10c7ce3f7abf59aecc91069cb879e5 /kernel/debug
parenta8649fb0a8c1de9c842c9c492f189cabbc468272 (diff)
kdb: Gid rid of implicit setting of the current task / regs
Some (but not all?) of the kdb backtrace paths would cause the kdb_current_task and kdb_current_regs to remain changed. As discussed in a review of a previous patch [1], this doesn't seem intuitive, so let's fix that. ...but, it turns out that there's actually no longer any reason to set the current task / current regs while backtracing anymore anyway. As of commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master") if we're backtracing on a task running on a CPU we ask that CPU to do the backtrace itself. Linux can do that without anything fancy. If we're doing backtrace on a sleeping task we can also do that fine without updating globals. So this patch mostly just turns into deleting a bunch of code. [1] https://lore.kernel.org/r/20191010150735.dhrj3pbjgmjrdpwr@holly.lan Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191109111624.4.Ibc3d982bbeb9e46872d43973ba808cd4c79537c7@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Diffstat (limited to 'kernel/debug')
-rw-r--r--kernel/debug/kdb/kdb_bt.c8
-rw-r--r--kernel/debug/kdb/kdb_main.c2
-rw-r--r--kernel/debug/kdb/kdb_private.h1
3 files changed, 2 insertions, 9 deletions
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 4af48ac53625..3de0cc780c16 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -119,7 +119,6 @@ kdb_bt_cpu(unsigned long cpu)
return;
}
- kdb_set_current_task(kdb_tsk);
kdb_bt1(kdb_tsk, ~0UL, false);
}
@@ -166,10 +165,8 @@ kdb_bt(int argc, const char **argv)
if (diag)
return diag;
p = find_task_by_pid_ns(pid, &init_pid_ns);
- if (p) {
- kdb_set_current_task(p);
+ if (p)
return kdb_bt1(p, ~0UL, false);
- }
kdb_printf("No process with pid == %ld found\n", pid);
return 0;
} else if (strcmp(argv[0], "btt") == 0) {
@@ -178,11 +175,9 @@ kdb_bt(int argc, const char **argv)
diag = kdbgetularg((char *)argv[1], &addr);
if (diag)
return diag;
- kdb_set_current_task((struct task_struct *)addr);
return kdb_bt1((struct task_struct *)addr, ~0UL, false);
} else if (strcmp(argv[0], "btc") == 0) {
unsigned long cpu = ~0;
- struct task_struct *save_current_task = kdb_current_task;
if (argc > 1)
return KDB_ARGCOUNT;
if (argc == 1) {
@@ -204,7 +199,6 @@ kdb_bt(int argc, const char **argv)
kdb_bt_cpu(cpu);
touch_nmi_watchdog();
}
- kdb_set_current_task(save_current_task);
}
return 0;
} else {
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 4d44b3746836..ba12e9f4661e 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1138,7 +1138,7 @@ static void kdb_dumpregs(struct pt_regs *regs)
console_loglevel = old_lvl;
}
-void kdb_set_current_task(struct task_struct *p)
+static void kdb_set_current_task(struct task_struct *p)
{
kdb_current_task = p;
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index e829b22f3946..2e296e4a234c 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -240,7 +240,6 @@ extern void *debug_kmalloc(size_t size, gfp_t flags);
extern void debug_kfree(void *);
extern void debug_kusage(void);
-extern void kdb_set_current_task(struct task_struct *);
extern struct task_struct *kdb_current_task;
extern struct pt_regs *kdb_current_regs;