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=0000000000000000a 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 statp in __torture_print_stats(), if it is NULL, just create a lock-torture-statistics message with zero statistic argument. Cc: Josh Triplett <[email protected]> Cc: Paul E. McKenney <[email protected]> Signed-off-by: Kefeng Wang <[email protected]> --- kernel/locking/locktorture.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 8ef1919..7f0cf9c 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -647,19 +647,23 @@ static void __torture_print_stats(char *page, bool fail = 0; int i, n_stress; long max = 0; - long min = statp[0].n_lock_acquired; + long min = 0; long long sum = 0; - n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; - for (i = 0; i < n_stress; i++) { - if (statp[i].n_lock_fail) - fail = true; - sum += statp[i].n_lock_acquired; - if (max < statp[i].n_lock_fail) - max = statp[i].n_lock_fail; - if (min > statp[i].n_lock_fail) - min = statp[i].n_lock_fail; + if (statp) { + min = statp[0].n_lock_acquired; + n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; + for (i = 0; i < n_stress; i++) { + if (statp[i].n_lock_fail) + fail = true; + sum += statp[i].n_lock_acquired; + if (max < statp[i].n_lock_fail) + max = statp[i].n_lock_fail; + if (min > statp[i].n_lock_fail) + min = statp[i].n_lock_fail; + } } + page += sprintf(page, "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n", write ? "Writes" : "Reads ", -- 2.6.0.GIT
