| Message ID | 1452650782-15099-1-git-send-email-wangkefeng.wang@huawei.com |
|---|---|
| State | New |
| Headers | show |
Hi paul, On 2016/1/14 0:27, Paul E. McKenney wrote: > On Wed, Jan 13, 2016 at 10:06:22AM +0800, Kefeng Wang wrote: >> Insmod locktorture with torture_type=mutex will lead to crash, >> >> Unable to handle kernel NULL pointer dereference at virtual address 00000008 >> pgd = ffffffc0f6c10000 >> [00000008] *pgd=000000013b221003, *pud=000000013b221003, *pmd=0000000000000000 >> Internal error: Oops: 94000006 [#1] PREEMPT SMP >> Modules linked in: locktorture(+) torture >> CPU: 2 PID: 1462 Comm: insmod Not tainted 4.4.0+ #19 >> Hardware name: linux,dummy-virt (DT) >> task: ffffffc0fb2b3700 ti: ffffffc0fa938000 task.ti: ffffffc0fa938000 >> PC is at __torture_print_stats+0x18/0x180 [locktorture] >> LR is at lock_torture_stats_print+0x68/0x110 [locktorture] >> pc : [<ffffffbffc017028>] lr : [<ffffffbffc017500>] pstate: 60000145 >> sp : ffffffc0fa93bb20 >> [snip...] >> Call trace: >> [<ffffffbffc017028>] __torture_print_stats+0x18/0x180 [locktorture] >> [<ffffffbffc017500>] lock_torture_stats_print+0x68/0x110 [locktorture] >> [<ffffffbffc0180fc>] lock_torture_cleanup+0xc4/0x278 [locktorture] >> [<ffffffbffc01d144>] lock_torture_init+0x144/0x5b0 [locktorture] >> [<ffffffc000082940>] do_one_initcall+0x94/0x1a0 >> [<ffffffc000141888>] do_init_module+0x60/0x1c8 >> [<ffffffc00011c628>] load_module+0x1880/0x1c9c >> [<ffffffc00011cc00>] SyS_finit_module+0x7c/0x88 >> [<ffffffc000085cb0>] el0_svc_naked+0x24/0x28 >> >> Fix it by check stats_task in lock_torture_cleanup() to guard not into >> a wrong path. >> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > Good catch! One question below... > >> --- >> kernel/locking/locktorture.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c >> index 8ef1919..1afa8ad 100644 >> --- a/kernel/locking/locktorture.c >> +++ b/kernel/locking/locktorture.c >> @@ -764,8 +764,10 @@ static void lock_torture_cleanup(void) >> reader_tasks = NULL; >> } >> >> - torture_stop_kthread(lock_torture_stats, stats_task); >> - lock_torture_stats_print(); /* -After- the stats thread is stopped! */ >> + if (stats_task) { >> + torture_stop_kthread(lock_torture_stats, stats_task); >> + lock_torture_stats_print(); /* -After- the stats thread is stopped! */ >> + } > > Does it work to have the following? > > + if (stats_task) > + torture_stop_kthread(lock_torture_stats, stats_task); > + lock_torture_stats_print(); /* -After- the stats thread is stopped! */ > > We need to print the statistics at the end of the run, even if we chose > not to print them periodically throughout the run. > No, the pc is in __torture_print_stats(char *page, struct lock_stress_stats *statp, bool write), that is 'long min = statp[0].n_lock_acquired;', if the torture_type is invalid, the statp is NULL, because the cxt.lwsa and cxt.lwsa/cxt.lrsa are not initialized in lock_torture_init(). Thanks, Kefeng > Thanx, Paul > >> if (atomic_read(&cxt.n_lock_torture_errors)) >> lock_torture_print_module_parms(cxt.cur_ops, >> -- >> 1.7.12.4 >> > > > . >
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 8ef1919..1afa8ad 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -764,8 +764,10 @@ static void lock_torture_cleanup(void) reader_tasks = NULL; } - torture_stop_kthread(lock_torture_stats, stats_task); - lock_torture_stats_print(); /* -After- the stats thread is stopped! */ + if (stats_task) { + torture_stop_kthread(lock_torture_stats, stats_task); + lock_torture_stats_print(); /* -After- the stats thread is stopped! */ + } if (atomic_read(&cxt.n_lock_torture_errors)) lock_torture_print_module_parms(cxt.cur_ops,
Insmod locktorture with torture_type=mutex will lead to crash, Unable to handle kernel NULL pointer dereference at virtual address 00000008 pgd = ffffffc0f6c10000 [00000008] *pgd=000000013b221003, *pud=000000013b221003, *pmd=0000000000000000 Internal error: Oops: 94000006 [#1] PREEMPT SMP Modules linked in: locktorture(+) torture CPU: 2 PID: 1462 Comm: insmod Not tainted 4.4.0+ #19 Hardware name: linux,dummy-virt (DT) task: ffffffc0fb2b3700 ti: ffffffc0fa938000 task.ti: ffffffc0fa938000 PC is at __torture_print_stats+0x18/0x180 [locktorture] LR is at lock_torture_stats_print+0x68/0x110 [locktorture] pc : [<ffffffbffc017028>] lr : [<ffffffbffc017500>] pstate: 60000145 sp : ffffffc0fa93bb20 [snip...] Call trace: [<ffffffbffc017028>] __torture_print_stats+0x18/0x180 [locktorture] [<ffffffbffc017500>] lock_torture_stats_print+0x68/0x110 [locktorture] [<ffffffbffc0180fc>] lock_torture_cleanup+0xc4/0x278 [locktorture] [<ffffffbffc01d144>] lock_torture_init+0x144/0x5b0 [locktorture] [<ffffffc000082940>] do_one_initcall+0x94/0x1a0 [<ffffffc000141888>] do_init_module+0x60/0x1c8 [<ffffffc00011c628>] load_module+0x1880/0x1c9c [<ffffffc00011cc00>] SyS_finit_module+0x7c/0x88 [<ffffffc000085cb0>] el0_svc_naked+0x24/0x28 Fix it by check stats_task in lock_torture_cleanup() to guard not into a wrong path. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- kernel/locking/locktorture.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) -- 1.7.12.4