Messages in this thread | | | From | Anders Roxell <> | Date | Tue, 20 Dec 2022 09:54:45 +0100 | Subject | Re: BUG: sleeping function called from invalid context at kernel/kallsyms.c:305 |
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On Sat, 17 Dec 2022 at 04:29, Leizhen (ThunderTown) <thunder.leizhen@huawei.com> wrote: > > > > On 2022/12/16 18:45, Anders Roxell wrote: > > Hi, > > > > I'm building an arm64 allmodconfig kernel (see the .config [1]) on > > yesterdays next tag 20221215 with KALLSYMS_SELFTEST enabled and I saw > > the following bug when the selftest ran: > > > > [29725.015182][ T58] BUG: sleeping function called from invalid > > context at kernel/kallsyms.c:305 > > [29725.022953][ T58] in_atomic(): 0, irqs_disabled(): 128, > > non_block: 0, pid: 58, name: kallsyms_test > > [29725.031272][ T58] preempt_count: 0, expected: 0 > > [29725.035903][ T58] RCU nest depth: 0, expected: 0 > > [29725.040574][ T58] no locks held by kallsyms_test/58. > > [29725.045494][ T58] irq event stamp: 18899904 > > [29725.049809][ T58] hardirqs last enabled at (18899903): > > finish_task_switch.isra.0 (core.c:?) > > [29725.059608][ T58] hardirqs last disabled at (18899904): > > test_perf_kallsyms_on_each_symbol (kallsyms_selftest.c:?) > > [29725.069936][ T58] softirqs last enabled at (18899886): __do_softirq (??:?) > > [29725.078670][ T58] softirqs last disabled at (18899879): > > ____do_softirq (irq.c:?) > > [29725.087399][ T58] CPU: 0 PID: 58 Comm: kallsyms_test Tainted: G > > T 6.1.0-next-20221215 #2 > > 0a142be8faea13ac333ed9a1cf4e71b6966ad16e > > [29725.099607][ T58] Hardware name: linux,dummy-virt (DT) > > [29725.104674][ T58] Call trace: > > [29725.107909][ T58] dump_backtrace (??:?) > > [29725.112706][ T58] show_stack (??:?) > > [29725.116883][ T58] dump_stack_lvl (??:?) > > [29725.121666][ T58] dump_stack (??:?) > > [29725.125852][ T58] __might_resched (??:?) > > [29725.130712][ T58] kallsyms_on_each_symbol (??:?) > > [29725.136018][ T58] test_perf_kallsyms_on_each_symbol (kallsyms_selftest.c:?) > > [29725.142008][ T58] test_entry (kallsyms_selftest.c:?) > > [29725.146312][ T58] kthread (kthread.c:?) > > [29725.150567][ T58] ret_from_fork (??:?) > > [29734.975283][ T58] kallsyms_selftest: kallsyms_on_each_symbol() > > traverse all: 5744310840 ns > > [29734.992268][ T58] kallsyms_selftest: > > kallsyms_on_each_match_symbol() traverse all: 1164580 ns > > [29735.049679][ T58] kallsyms_selftest: finish > > > > looks like the issue is that test_perf_kallsyms_on_each_symbol() does > > these function calls: > > > > local_irq_save(flags); > > t0 = sched_clock(); > > kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat); > > t1 = sched_clock(); > > local_irq_restore(flags); > > > > and inside kallsyms_on_each_match_symbol(), cond_resched() is called. > > > > Any ideas how to solve this? > > I was initially hoping that the test process would not be interrupted. > It is not a big problem to remove local_irq_save(). From a probabilistic > statistical point of view: it does not affect the horizontal comparison > between kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol(), > and the vertical comparison before and after optimization is also not > affected. > > Or do not call cond_resched() during the test. This method seems to be > a little better.
I tried this patch and yes it made the kallsyms selftest to finish.
Please send a patch.
Cheers, Anders
> > diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c > index e31b4d87a4e1b71..9e07fabaf08e647 100644 > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -358,7 +358,8 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, > ret = fn(data, namebuf, NULL, kallsyms_sym_address(i)); > if (ret != 0) > return ret; > - cond_resched(); > + if (!IS_ENABLED(CONFIG_KALLSYMS_SELFTEST)) > + cond_resched(); > } > return 0; > } > @@ -375,7 +376,8 @@ int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long), > > for (i = start; !ret && i <= end; i++) { > ret = fn(data, kallsyms_sym_address(get_symbol_seq(i))); > - cond_resched(); > + if (!IS_ENABLED(CONFIG_KALLSYMS_SELFTEST)) > + cond_resched(); > } > > return ret; > > > > > Cheers, > > Anders > > [1] https://people.linaro.org/~anders.roxell/next-20221215.config > > . > > > > -- > Regards, > Zhen Lei
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