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| author | Rusty Russell <rusty@rustcorp.com.au> | 2010-05-31 19:53:50 +0930 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-31 11:21:32 -0700 |
| commit | 293a7cfeedc2b2380a7c7274902323c3cf5f7575 (patch) | |
| tree | 00576870400cb640fe92ea3f525338e6e3733a2e /kernel | |
| parent | 67a3e12b05e055c0415c556a315a3d3eb637e29e (diff) | |
| download | lwn-293a7cfeedc2b2380a7c7274902323c3cf5f7575.tar.gz lwn-293a7cfeedc2b2380a7c7274902323c3cf5f7575.zip | |
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.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/module.c b/kernel/module.c index 333fbcc96978..d806e00e4450 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); |