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authorRusty Russell <rusty@rustcorp.com.au>2010-05-31 19:53:50 +0930
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-31 11:21:32 -0700
commit293a7cfeedc2b2380a7c7274902323c3cf5f7575 (patch)
tree00576870400cb640fe92ea3f525338e6e3733a2e /kernel
parent67a3e12b05e055c0415c556a315a3d3eb637e29e (diff)
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module: fix reference to mod->percpu after freeing module.
Rafael sees a sometimes crash at precpu_modfree from kernel/module.c; it only occurred with another (since-reverted) patch, but that patch simply changed timing to uncover this bug, it was otherwise unrelated. The comment about the mod being freed is self-explanatory, but neither Tejun nor I read it. This bug was introduced in 259354deaa, after it had previously been fixed in 6e2b75740b. How embarrassing. Reported-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Embarrassingly-Acked-by: Tejun Heo <tj@kernel.org> Cc: Masami Hiramatsu <mhiramat@redhat.com> Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/module.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 333fbcc9697..d806e00e445 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2014,6 +2014,7 @@ static noinline struct module *load_module(void __user *umod,
long err = 0;
void *ptr = NULL; /* Stops spurious gcc warning */
unsigned long symoffs, stroffs, *strmap;
+ void __percpu *percpu;
mm_segment_t old_fs;
@@ -2158,6 +2159,8 @@ static noinline struct module *load_module(void __user *umod,
goto free_mod;
sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
+ /* Keep this around for failure path. */
+ percpu = mod_percpu(mod);
/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any
@@ -2463,7 +2466,7 @@ static noinline struct module *load_module(void __user *umod,
module_free(mod, mod->module_core);
/* mod will be freed with core. Don't access it beyond this line! */
free_percpu:
- percpu_modfree(mod);
+ free_percpu(percpu);
free_mod:
kfree(args);
kfree(strmap);