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| author |   Douglas Anderson <dianders@chromium.org> | 2019-11-09 11:16:43 -0800 |
|---|---|---|
| committer |   Daniel Thompson <daniel.thompson@linaro.org> | 2020-01-31 17:34:00 +0000 |
| commit | 9441d5f6b77770ee388884f04b14a99b028a15e6 (patch) | |
| tree | 2061f7a95b10c7ce3f7abf59aecc91069cb879e5 /kernel | |
| parent | kdb: kdb_current_task shouldn't be exported (diff) | |
| download | linux-dev-9441d5f6b77770ee388884f04b14a99b028a15e6.tar.xz linux-dev-9441d5f6b77770ee388884f04b14a99b028a15e6.zip | |
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')
| -rw-r--r-- | kernel/debug/kdb/kdb_bt.c | 8 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_main.c | 2 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_private.h | 1 |
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; |