Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2024-12-29 17:22:07 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

preempt: Move PREEMPT_RT before PREEMPT in vermagic.

Browse Source 
Since the dynamic preemption has been enabled for PREEMPT_RT we have now
CONFIG_PREEMPT and CONFIG_PREEMPT_RT set simultaneously. This affects
the vermagic strings which comes now PREEMPT with PREEMPT_RT enabled.

The PREEMPT_RT module usually can not be loaded on a PREEMPT kernel
because some symbols are missing.
However if the symbols are fine then it continues and it crashes later.
The problem is that the struct module has a different layout and the
num_exentries or init members are at a different position leading to a
crash later on. This is not necessary caught by the size check in
elf_validity_cache_index_mod() because the mem member has an alignment
requirement of __module_memory_align which is big enough keep the total
size unchanged. Therefore we should keep the string accurate instead of
removing it.

Move the PREEMPT_RT check before the PREEMPT so that it takes precedence
if both symbols are enabled.

Fixes: 35772d627b ("sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Link: https://lore.kernel.org/r/20241205160602.3lIAsJRT@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
This commit is contained in:
Sebastian Andrzej Siewior 2024-12-05 17:06:02 +01:00 committed by Petr Pavlu
parent 78d4f34e21
commit b8c5d884f9
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/vermagic.h
View File

@ -15,10 +15,10 @@
#else #else
#define MODULE_VERMAGIC_SMP "" #define MODULE_VERMAGIC_SMP ""
#endif #endif
#ifdef CONFIG_PREEMPT_BUILD #ifdef CONFIG_PREEMPT_RT
#define MODULE_VERMAGIC_PREEMPT "preempt "
#elif defined(CONFIG_PREEMPT_RT)
#define MODULE_VERMAGIC_PREEMPT "preempt_rt " #define MODULE_VERMAGIC_PREEMPT "preempt_rt "
#elif defined(CONFIG_PREEMPT_BUILD)
#define MODULE_VERMAGIC_PREEMPT "preempt "
#else #else
#define MODULE_VERMAGIC_PREEMPT "" #define MODULE_VERMAGIC_PREEMPT ""
#endif #endif