5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit a145c848d69f9c6f32008d8319edaa133360dd74 ]
dereference_symbol_descriptor() needs to obtain the module pointer belonging to pointer in order to resolve that pointer. The returned mod pointer is obtained under RCU-sched/ preempt_disable() guarantees and needs to be used within this section to ensure that the module is not removed in the meantime.
Extend the preempt_disable() section to also cover dereference_module_function_descriptor().
Fixes: 04b8eb7a4ccd9 ("symbol lookup: introduce dereference_symbol_descriptor()") Cc: James E.J. Bottomley James.Bottomley@HansenPartnership.com Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: Helge Deller deller@gmx.de Cc: Madhavan Srinivasan maddy@linux.ibm.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Naveen N Rao naveen@kernel.org Cc: Nicholas Piggin npiggin@gmail.com Cc: Sergey Senozhatsky sergey.senozhatsky.work@gmail.com Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Reviewed-by: Sergey Senozhatsky senozhatsky@chromium.org Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Link: https://lore.kernel.org/r/20250108090457.512198-2-bigeasy@linutronix.de Signed-off-by: Petr Pavlu petr.pavlu@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/kallsyms.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 1f96ce2b47df1..d84b677c728a9 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -63,10 +63,10 @@ static inline void *dereference_symbol_descriptor(void *ptr)
preempt_disable(); mod = __module_address((unsigned long)ptr); - preempt_enable();
if (mod) ptr = dereference_module_function_descriptor(mod, ptr); + preempt_enable(); #endif return ptr; }