diff options
| author | Lukasz Bartosik <lb@semihalf.com> | 2021-04-02 00:51:49 +0200 |
|---|---|---|
| committer | Stephen Boyd <sboyd@kernel.org> | 2021-04-02 23:56:14 -0700 |
| commit | 7045465500e465b09f09d6e5bdc260a9f1aab97b (patch) | |
| tree | 968ff4639e56b0d9085d3e4f7c8d56d7e3e84563 /drivers/clk/clk.c | |
| parent | 8d3c0c01cb2e36b2bf3c06a82b18b228d0c8f5d0 (diff) | |
clk: fix invalid usage of list cursor in unregister
Fix invalid usage of a list_for_each_entry cursor in
clk_notifier_unregister(). When list is empty or if the list
is completely traversed (without breaking from the loop on one
of the entries) then the list cursor does not point to a valid
entry and therefore should not be used. The patch fixes a logical
bug that hasn't been seen in pratice however it is analogus
to the bug fixed in clk_notifier_register().
The issue was dicovered when running 5.12-rc1 kernel on x86_64
with KASAN enabled:
BUG: KASAN: global-out-of-bounds in clk_notifier_register+0xab/0x230
Read of size 8 at addr ffffffffa0d10588 by task swapper/0/1
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc1 #1
Hardware name: Google Caroline/Caroline,
BIOS Google_Caroline.7820.430.0 07/20/2018
Call Trace:
dump_stack+0xee/0x15c
print_address_description+0x1e/0x2dc
kasan_report+0x188/0x1ce
? clk_notifier_register+0xab/0x230
? clk_prepare_lock+0x15/0x7b
? clk_notifier_register+0xab/0x230
clk_notifier_register+0xab/0x230
dw8250_probe+0xc01/0x10d4
...
Memory state around the buggy address:
ffffffffa0d10480: 00 00 00 00 00 03 f9 f9 f9 f9 f9 f9 00 00 00 00
ffffffffa0d10500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9
>ffffffffa0d10580: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00
^
ffffffffa0d10600: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00
ffffffffa0d10680: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
==================================================================
Fixes: b2476490ef11 ("clk: introduce the common clock framework")
Reported-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Lukasz Bartosik <lb@semihalf.com>
Link: https://lore.kernel.org/r/20210401225149.18826-2-lb@semihalf.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 30 |
1 files changed, 13 insertions, 17 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 16634d5912be..39cfc6c6a8d2 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -4394,32 +4394,28 @@ EXPORT_SYMBOL_GPL(clk_notifier_register); */ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) { - struct clk_notifier *cn = NULL; - int ret = -EINVAL; + struct clk_notifier *cn; + int ret = -ENOENT; if (!clk || !nb) return -EINVAL; clk_prepare_lock(); - list_for_each_entry(cn, &clk_notifier_list, node) - if (cn->clk == clk) - break; - - if (cn->clk == clk) { - ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); + list_for_each_entry(cn, &clk_notifier_list, node) { + if (cn->clk == clk) { + ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); - clk->core->notifier_count--; + clk->core->notifier_count--; - /* XXX the notifier code should handle this better */ - if (!cn->notifier_head.head) { - srcu_cleanup_notifier_head(&cn->notifier_head); - list_del(&cn->node); - kfree(cn); + /* XXX the notifier code should handle this better */ + if (!cn->notifier_head.head) { + srcu_cleanup_notifier_head(&cn->notifier_head); + list_del(&cn->node); + kfree(cn); + } + break; } - - } else { - ret = -ENOENT; } clk_prepare_unlock(); |