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SubjectBUG: sleeping function called from invalid context at kernel/kallsyms.c:305
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?

Cheers,
Anders
[1] https://people.linaro.org/~anders.roxell/next-20221215.config

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