From de6848b4877030b929d5619853c7e6c6e05a519b Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 30 Jun 2022 11:26:44 +0200 Subject: [PATCH] 5.15-stable patches added patches: tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch --- queue-5.15/series | 1 + ..._init-annotated-tick_nohz_full_setup.patch | 49 +++++++++++++++++++ 2 files changed, 50 insertions(+) create mode 100644 queue-5.15/series create mode 100644 queue-5.15/tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch diff --git a/queue-5.15/series b/queue-5.15/series new file mode 100644 index 00000000000..4c96f37a3df --- /dev/null +++ b/queue-5.15/series @@ -0,0 +1 @@ +tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch diff --git a/queue-5.15/tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch b/queue-5.15/tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch new file mode 100644 index 00000000000..373cafb3b3b --- /dev/null +++ b/queue-5.15/tick-nohz-unexport-__init-annotated-tick_nohz_full_setup.patch @@ -0,0 +1,49 @@ +From 2390095113e98fc52fffe35c5206d30d9efe3f78 Mon Sep 17 00:00:00 2001 +From: Masahiro Yamada +Date: Mon, 27 Jun 2022 12:22:09 +0900 +Subject: tick/nohz: unexport __init-annotated tick_nohz_full_setup() + +From: Masahiro Yamada + +commit 2390095113e98fc52fffe35c5206d30d9efe3f78 upstream. + +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 +Signed-off-by: Masahiro Yamada +Tested-by: Paul E. McKenney +Signed-off-by: Linus Torvalds +Cc: Thomas Backlund +Signed-off-by: Greg Kroah-Hartman +--- + kernel/time/tick-sched.c | 1 - + 1 file changed, 1 deletion(-) + +--- a/kernel/time/tick-sched.c ++++ b/kernel/time/tick-sched.c +@@ -509,7 +509,6 @@ void __init tick_nohz_full_setup(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) + { -- 2.47.3