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    Subject[PATCH 5.14 667/849] nfsd: dont alloc under spinlock in rpc_parse_scope_id
    Date
    From: J. Bruce Fields <bfields@redhat.com>

    [ Upstream commit 9b6e27d01adcec58e046c624874f8a124e8b07ec ]

    Dan Carpenter says:

    The patch d20c11d86d8f: "nfsd: Protect session creation and client
    confirm using client_lock" from Jul 30, 2014, leads to the following
    Smatch static checker warning:

    net/sunrpc/addr.c:178 rpc_parse_scope_id()
    warn: sleeping in atomic context

    Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
    Fixes: d20c11d86d8f ("nfsd: Protect session creation and client...")
    Signed-off-by: J. Bruce Fields <bfields@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/sunrpc/addr.c | 40 ++++++++++++++++++----------------------
    1 file changed, 18 insertions(+), 22 deletions(-)

    diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c
    index 6e4dbd577a39f..d435bffc61999 100644
    --- a/net/sunrpc/addr.c
    +++ b/net/sunrpc/addr.c
    @@ -162,8 +162,10 @@ static int rpc_parse_scope_id(struct net *net, const char *buf,
    const size_t buflen, const char *delim,
    struct sockaddr_in6 *sin6)
    {
    - char *p;
    + char p[IPV6_SCOPE_ID_LEN + 1];
    size_t len;
    + u32 scope_id = 0;
    + struct net_device *dev;

    if ((buf + buflen) == delim)
    return 1;
    @@ -175,29 +177,23 @@ static int rpc_parse_scope_id(struct net *net, const char *buf,
    return 0;

    len = (buf + buflen) - delim - 1;
    - p = kmemdup_nul(delim + 1, len, GFP_KERNEL);
    - if (p) {
    - u32 scope_id = 0;
    - struct net_device *dev;
    -
    - dev = dev_get_by_name(net, p);
    - if (dev != NULL) {
    - scope_id = dev->ifindex;
    - dev_put(dev);
    - } else {
    - if (kstrtou32(p, 10, &scope_id) != 0) {
    - kfree(p);
    - return 0;
    - }
    - }
    -
    - kfree(p);
    -
    - sin6->sin6_scope_id = scope_id;
    - return 1;
    + if (len > IPV6_SCOPE_ID_LEN)
    + return 0;
    +
    + memcpy(p, delim + 1, len);
    + p[len] = 0;
    +
    + dev = dev_get_by_name(net, p);
    + if (dev != NULL) {
    + scope_id = dev->ifindex;
    + dev_put(dev);
    + } else {
    + if (kstrtou32(p, 10, &scope_id) != 0)
    + return 0;
    }

    - return 0;
    + sin6->sin6_scope_id = scope_id;
    + return 1;
    }

    static size_t rpc_pton6(struct net *net, const char *buf, const size_t buflen,
    --
    2.33.0


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