path: root/kernel/module.c
diff options
authorTrent Piepho <xyzzy@speakeasy.org>2006-05-15 09:44:06 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-15 11:20:55 -0700
commit5e376613899076396d0c97de67ad072587267370 (patch)
treeecc15c25ee4da7754aa7d137dccebab68820399e /kernel/module.c
parent[PATCH] s390: add vmsplice system call (diff)
[PATCH] symbol_put_addr() locks kernel
Even since a previous patch: Fix race between CONFIG_DEBUG_SLABALLOC and modules Sun, 27 Jun 2004 17:55:19 +0000 (17:55 +0000) http://www.kernel.org/git/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commit;h=92b3db26d31cf21b70e3c1eadc56c179506d8fbe The function symbol_put_addr() will deadlock the kernel. symbol_put_addr() would acquire modlist_lock, then while holding the lock call two functions kernel_text_address() and module_text_address() which also try to acquire the same lock. This deadlocks the kernel of course. This patch changes symbol_put_addr() to not acquire the modlist_lock, it doesn't need it since it never looks at the module list directly. Also, it now uses core_kernel_text() instead of kernel_text_address(). The latter has an additional check for addr inside a module, but we don't need to do that since we call module_text_address() (the same function kernel_text_address uses) ourselves. Signed-off-by: Trent Piepho <xyzzy@speakeasy.org> Cc: Zwane Mwaikambo <zwane@fsmlabs.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Johannes Stezenbach <js@linuxtv.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to '')
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/module.c b/kernel/module.c
index d24deb0dbbc9..bbe04862e1b0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -705,14 +705,14 @@ EXPORT_SYMBOL(__symbol_put);
void symbol_put_addr(void *addr)
- unsigned long flags;
+ struct module *modaddr;
- spin_lock_irqsave(&modlist_lock, flags);
- if (!kernel_text_address((unsigned long)addr))
- BUG();
+ if (core_kernel_text((unsigned long)addr))
+ return;
- module_put(module_text_address((unsigned long)addr));
- spin_unlock_irqrestore(&modlist_lock, flags);
+ if (!(modaddr = module_text_address((unsigned long)addr)))
+ BUG();
+ module_put(modaddr);