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| author | Miroslav Benes <mbenes@suse.cz> | 2015-06-01 18:48:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-21 20:10:13 +0300 |
| commit | 7012248100a1203f9936d6eab7b1d78e0f569218 (patch) | |
| tree | 7993b3f06bb695527080c52d4933499ecb10e7f7 | |
| parent | e495fecb2b5e45a8e5d5ca49238e4b59977e8ec9 (diff) | |
| download | linux-7012248100a1203f9936d6eab7b1d78e0f569218.tar.xz | |
livepatch: add module locking around kallsyms calls
commit 9a1bd63cdae4b623494c4ebaf723a91c35ec49fb upstream.
The list of loaded modules is walked through in
module_kallsyms_on_each_symbol (called by kallsyms_on_each_symbol). The
module_mutex lock should be acquired to prevent potential corruptions
in the list.
This was uncovered with new lockdep asserts in module code introduced by
the commit 0be964be0d45 ("module: Sanitize RCU usage and locking") in
recent next- trees.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/livepatch/core.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 3f9f1d6b4c2e..8ba4f9f2e44e 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -179,7 +179,9 @@ static int klp_find_object_symbol(const char *objname, const char *name, .count = 0 }; + mutex_lock(&module_mutex); kallsyms_on_each_symbol(klp_find_callback, &args); + mutex_unlock(&module_mutex); if (args.count == 0) pr_err("symbol '%s' not found in symbol table\n", name); @@ -219,13 +221,19 @@ static int klp_verify_vmlinux_symbol(const char *name, unsigned long addr) .name = name, .addr = addr, }; + int ret; - if (kallsyms_on_each_symbol(klp_verify_callback, &args)) - return 0; + mutex_lock(&module_mutex); + ret = kallsyms_on_each_symbol(klp_verify_callback, &args); + mutex_unlock(&module_mutex); - pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n", - name, addr); - return -EINVAL; + if (!ret) { + pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n", + name, addr); + return -EINVAL; + } + + return 0; } static int klp_find_verify_func_addr(struct klp_object *obj, |