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firewire: remove check of list iterator against head past the loop body

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When list_for_each_entry() completes the iteration over the whole list
without breaking the loop, the iterator value will be a bogus pointer
computed based on the head element.

While it is safe to use the pointer to determine if it was computed
based on the head element, either with list_entry_is_head() or
&pos->member == head, using the iterator variable after the loop should
be avoided.

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element [1].

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Cc: <stable@vger.kernel.org>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220409041243.603210-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Jakob Koschel 2022-04-09 13:12:42 +09:00 committed by Takashi Iwai
parent b7c81f8024
commit 9423973869
2 changed files with 23 additions and 20 deletions
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30
drivers/firewire/core-transaction.c
View file

@ -73,24 +73,25 @@ static int try_cancel_split_timeout(struct fw_transaction *t)
static int close_transaction(struct fw_transaction *transaction,
struct fw_card *card, int rcode)
{
struct fw_transaction *t;
struct fw_transaction *t = NULL, *iter;
unsigned long flags;
spin_lock_irqsave(&card->lock, flags);
list_for_each_entry(t, &card->transaction_list, link) {
if (t == transaction) {
if (!try_cancel_split_timeout(t)) {
list_for_each_entry(iter, &card->transaction_list, link) {
if (iter == transaction) {
if (!try_cancel_split_timeout(iter)) {
spin_unlock_irqrestore(&card->lock, flags);
goto timed_out;
}
list_del_init(&t->link);
card->tlabel_mask &= ~(1ULL << t->tlabel);
list_del_init(&iter->link);
card->tlabel_mask &= ~(1ULL << iter->tlabel);
t = iter;
break;
}
}
spin_unlock_irqrestore(&card->lock, flags);
if (&t->link != &card->transaction_list) {
if (t) {
t->callback(card, rcode, NULL, 0, t->callback_data);
return 0;
}
@ -935,7 +936,7 @@ EXPORT_SYMBOL(fw_core_handle_request);
void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
{
struct fw_transaction *t;
struct fw_transaction *t = NULL, *iter;
unsigned long flags;
u32 *data;
size_t data_length;
@ -947,20 +948,21 @@ void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
rcode = HEADER_GET_RCODE(p->header[1]);
spin_lock_irqsave(&card->lock, flags);
list_for_each_entry(t, &card->transaction_list, link) {
if (t->node_id == source && t->tlabel == tlabel) {
if (!try_cancel_split_timeout(t)) {
list_for_each_entry(iter, &card->transaction_list, link) {
if (iter->node_id == source && iter->tlabel == tlabel) {
if (!try_cancel_split_timeout(iter)) {
spin_unlock_irqrestore(&card->lock, flags);
goto timed_out;
}
list_del_init(&t->link);
card->tlabel_mask &= ~(1ULL << t->tlabel);
list_del_init(&iter->link);
card->tlabel_mask &= ~(1ULL << iter->tlabel);
t = iter;
break;
}
}
spin_unlock_irqrestore(&card->lock, flags);
if (&t->link == &card->transaction_list) {
if (!t) {
timed_out:
fw_notice(card, "unsolicited response (source %x, tlabel %x)\n",
source, tlabel);

13
drivers/firewire/sbp2.c
View file

@ -408,7 +408,7 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
void *payload, size_t length, void *callback_data)
{
struct sbp2_logical_unit *lu = callback_data;
struct sbp2_orb *orb;
struct sbp2_orb *orb = NULL, *iter;
struct sbp2_status status;
unsigned long flags;
@ -433,17 +433,18 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
/* Lookup the orb corresponding to this status write. */
spin_lock_irqsave(&lu->tgt->lock, flags);
list_for_each_entry(orb, &lu->orb_list, link) {
list_for_each_entry(iter, &lu->orb_list, link) {
if (STATUS_GET_ORB_HIGH(status) == 0 &&
STATUS_GET_ORB_LOW(status) == orb->request_bus) {
orb->rcode = RCODE_COMPLETE;
list_del(&orb->link);
STATUS_GET_ORB_LOW(status) == iter->request_bus) {
iter->rcode = RCODE_COMPLETE;
list_del(&iter->link);
orb = iter;
break;
}
}
spin_unlock_irqrestore(&lu->tgt->lock, flags);
if (&orb->link != &lu->orb_list) {
if (orb) {
orb->callback(orb, &status);
kref_put(&orb->kref, free_orb); /* orb callback reference */
} else {