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| author |   Masahiro Yamada <masahiroy@kernel.org> | 2022-06-27 12:22:09 +0900 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2022-06-27 10:43:12 -0700 |
| commit | 2390095113e98fc52fffe35c5206d30d9efe3f78 (patch) | |
| tree | 02490601f66b8a782ce60b1a3e227146855e9885 | |
| parent | Linux 5.19-rc4 (diff) | |
| download | linux-2390095113e98fc52fffe35c5206d30d9efe3f78.tar.xz linux-2390095113e98fc52fffe35c5206d30d9efe3f78.zip | |
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>
| -rw-r--r-- | kernel/time/tick-sched.c | 1 |
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) { |