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authorMasahiro Yamada <masahiroy@kernel.org>2022-06-27 12:22:09 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2022-06-27 10:43:12 -0700
commit2390095113e98fc52fffe35c5206d30d9efe3f78 (patch)
tree02490601f66b8a782ce60b1a3e227146855e9885 /kernel/time
parent03c765b0e3b4cb5063276b086c76f7a612856a9a (diff)
tick/nohz: unexport __init-annotated tick_nohz_full_setup()
EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic. modpost used to detect it, but it had been broken for a decade. Commit 28438794aba4 ("modpost: fix section mismatch check for exported init/exit sections") fixed it so modpost started to warn it again, then this showed up: MODPOST vmlinux.symvers WARNING: modpost: vmlinux.o(___ksymtab_gpl+tick_nohz_full_setup+0x0): Section mismatch in reference from the variable __ksymtab_tick_nohz_full_setup to the function .init.text:tick_nohz_full_setup() The symbol tick_nohz_full_setup is exported and annotated __init Fix this by removing the __init annotation of tick_nohz_full_setup or drop the export. Drop the export because tick_nohz_full_setup() is only called from the built-in code in kernel/sched/isolation.c. Fixes: ae9e557b5be2 ("time: Export tick start/stop functions for rcutorture") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 58a11f859ac7..30049580cd62 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -526,7 +526,6 @@ void __init tick_nohz_full_setup(cpumask_var_t cpumask)
cpumask_copy(tick_nohz_full_mask, cpumask);
tick_nohz_full_running = true;
}
-EXPORT_SYMBOL_GPL(tick_nohz_full_setup);
static int tick_nohz_cpu_down(unsigned int cpu)
{