| Message ID | 20250108090457.512198-2-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,01/28] module: Extend the preempt disabled section in dereference_symbol_descriptor(). | expand |
On 1/8/25 10:04, Sebastian Andrzej Siewior wrote: > 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> Nice catch. Acked-by: Helge Deller <deller@gmx.de> This patch really should be backported. Can you add a Cc: stable tag? Helge > --- > 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 c3f075e8f60cb..1c6a6c1704d8d 100644 > --- a/include/linux/kallsyms.h > +++ b/include/linux/kallsyms.h > @@ -57,10 +57,10 @@ 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; > }
On 2025-01-08 10:55:04 [+0100], Helge Deller wrote: > Nice catch. > > Acked-by: Helge Deller <deller@gmx.de> > > This patch really should be backported. > Can you add a Cc: stable tag? It should be picked due to the fixes tag. I add it if I am going to repost it. > Helge Sebastian
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index c3f075e8f60cb..1c6a6c1704d8d 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -57,10 +57,10 @@ 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; }
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> --- include/linux/kallsyms.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)