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authorWen Gu <guwen@linux.alibaba.com>2022-02-09 22:10:53 +0800
committerDavid S. Miller <davem@davemloft.net>2022-02-11 11:10:29 +0000
commit1de9770d121ee9294794cca0e0be8fbfa0134ee8 (patch)
tree77ff12066badf957f909524b081bd2ad37c292e1 /net
parentf1baf68e1383f6ed93eb9cff2866d46562607a43 (diff)
net/smc: Avoid overwriting the copies of clcsock callback functions
The callback functions of clcsock will be saved and replaced during the fallback. But if the fallback happens more than once, then the copies of these callback functions will be overwritten incorrectly, resulting in a loop call issue: clcsk->sk_error_report |- smc_fback_error_report() <------------------------------| |- smc_fback_forward_wakeup() | (loop) |- clcsock_callback() (incorrectly overwritten) | |- smc->clcsk_error_report() ------------------| So this patch fixes the issue by saving these function pointers only once in the fallback and avoiding overwriting. Reported-by: syzbot+4de3c0e8a263e1e499bc@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/0000000000006d045e05d78776f6@google.com Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/smc/af_smc.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8c89d0b0ca18..306d9e8cd1dd 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -667,14 +667,17 @@ static void smc_fback_error_report(struct sock *clcsk)
static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code)
{
struct sock *clcsk;
+ int rc = 0;
mutex_lock(&smc->clcsock_release_lock);
if (!smc->clcsock) {
- mutex_unlock(&smc->clcsock_release_lock);
- return -EBADF;
+ rc = -EBADF;
+ goto out;
}
clcsk = smc->clcsock->sk;
+ if (smc->use_fallback)
+ goto out;
smc->use_fallback = true;
smc->fallback_rsn = reason_code;
smc_stat_fallback(smc);
@@ -702,8 +705,9 @@ static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code)
smc->clcsock->sk->sk_user_data =
(void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY);
}
+out:
mutex_unlock(&smc->clcsock_release_lock);
- return 0;
+ return rc;
}
/* fall back during connect */