Commit 4e6a0535dd036377961027262aecb138099f925d
Committed by
Ingo Molnar
Ingo Molnar
1 parent
ad118c54a3
Exists in
master
and in
7 other branches
backtrace: replace timer with tasklet + completions
On qemu, the backtrace would show up _after_ the "end of backtrace testing" message. This patch changes it to use completions instead, which will guarantee that no such race exists. Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Showing 1 changed file with 26 additions and 11 deletions Side-by-side Diff
kernel/backtracetest.c
| ... | ... | @@ -10,18 +10,39 @@ |
| 10 | 10 | * of the License. |
| 11 | 11 | */ |
| 12 | 12 | |
| 13 | +#include <linux/completion.h> | |
| 13 | 14 | #include <linux/delay.h> |
| 15 | +#include <linux/interrupt.h> | |
| 14 | 16 | #include <linux/module.h> |
| 15 | 17 | #include <linux/sched.h> |
| 16 | 18 | #include <linux/stacktrace.h> |
| 17 | 19 | |
| 18 | -static struct timer_list backtrace_timer; | |
| 20 | +static void backtrace_test_normal(void) | |
| 21 | +{ | |
| 22 | + printk("Testing a backtrace from process context.\n"); | |
| 23 | + printk("The following trace is a kernel self test and not a bug!\n"); | |
| 19 | 24 | |
| 20 | -static void backtrace_test_timer(unsigned long data) | |
| 25 | + dump_stack(); | |
| 26 | +} | |
| 27 | + | |
| 28 | +static DECLARE_COMPLETION(backtrace_work); | |
| 29 | + | |
| 30 | +static void backtrace_test_irq_callback(unsigned long data) | |
| 21 | 31 | { |
| 32 | + dump_stack(); | |
| 33 | + complete(&backtrace_work); | |
| 34 | +} | |
| 35 | + | |
| 36 | +static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0); | |
| 37 | + | |
| 38 | +static void backtrace_test_irq(void) | |
| 39 | +{ | |
| 22 | 40 | printk("Testing a backtrace from irq context.\n"); |
| 23 | 41 | printk("The following trace is a kernel self test and not a bug!\n"); |
| 24 | - dump_stack(); | |
| 42 | + | |
| 43 | + init_completion(&backtrace_work); | |
| 44 | + tasklet_schedule(&backtrace_tasklet); | |
| 45 | + wait_for_completion(&backtrace_work); | |
| 25 | 46 | } |
| 26 | 47 | |
| 27 | 48 | #ifdef CONFIG_STACKTRACE |
| 28 | 49 | |
| 29 | 50 | |
| ... | ... | @@ -51,17 +72,11 @@ |
| 51 | 72 | static int backtrace_regression_test(void) |
| 52 | 73 | { |
| 53 | 74 | printk("====[ backtrace testing ]===========\n"); |
| 54 | - printk("Testing a backtrace from process context.\n"); | |
| 55 | - printk("The following trace is a kernel self test and not a bug!\n"); | |
| 56 | - dump_stack(); | |
| 57 | 75 | |
| 76 | + backtrace_test_normal(); | |
| 77 | + backtrace_test_irq(); | |
| 58 | 78 | backtrace_test_saved(); |
| 59 | 79 | |
| 60 | - init_timer(&backtrace_timer); | |
| 61 | - backtrace_timer.function = backtrace_test_timer; | |
| 62 | - mod_timer(&backtrace_timer, jiffies + 10); | |
| 63 | - | |
| 64 | - msleep(10); | |
| 65 | 80 | printk("====[ end of backtrace testing ]====\n"); |
| 66 | 81 | return 0; |
| 67 | 82 | } |