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  9. Jun 22, 2011
    • Xufeng Zhang's avatar
      udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet · 9cfaa8de
      Xufeng Zhang authored 
      

Consider this scenario: When the size of the first received udp packet
is bigger than the receive buffer, MSG_TRUNC bit is set in msg->msg_flags.
However, if checksum error happens and this is a blocking socket, it will
goto try_again loop to receive the next packet.  But if the size of the
next udp packet is smaller than receive buffer, MSG_TRUNC flag should not
be set, but because MSG_TRUNC bit is not cleared in msg->msg_flags before
receive the next packet, MSG_TRUNC is still set, which is wrong.

Fix this problem by clearing MSG_TRUNC flag when starting over for a
new packet.

Signed-off-by: default avatarXufeng Zhang <xufeng.zhang@windriver.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9cfaa8de
    • Xufeng Zhang's avatar
      ipv6/udp: Use the correct variable to determine non-blocking condition · 32c90254
      Xufeng Zhang authored 
      

udpv6_recvmsg() function is not using the correct variable to determine
whether or not the socket is in non-blocking operation, this will lead
to unexpected behavior when a UDP checksum error occurs.

Consider a non-blocking udp receive scenario: when udpv6_recvmsg() is
called by sock_common_recvmsg(), MSG_DONTWAIT bit of flags variable in
udpv6_recvmsg() is cleared by "flags & ~MSG_DONTWAIT" in this call:

    err = sk->sk_prot->recvmsg(iocb, sk, msg, size, flags & MSG_DONTWAIT,
                   flags & ~MSG_DONTWAIT, &addr_len);

i.e. with udpv6_recvmsg() getting these values:

	int noblock = flags & MSG_DONTWAIT
	int flags = flags & ~MSG_DONTWAIT

So, when udp checksum error occurs, the execution will go to
csum_copy_err, and then the problem happens:

    csum_copy_err:
            ...............
            if (flags & MSG_DONTWAIT)
                    return -EAGAIN;
            goto try_again;
            ...............

But it will always go to try_again as MSG_DONTWAIT has been cleared
from flags at call time -- only noblock contains the original value
of MSG_DONTWAIT, so the test should be:

            if (noblock)
                    return -EAGAIN;

This is also consistent with what the ipv4/udp code does.

Signed-off-by: default avatarXufeng Zhang <xufeng.zhang@windriver.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      32c90254
    • Randy Dunlap's avatar
      netconsole: fix build when CONFIG_NETCONSOLE_DYNAMIC is turned on · 58fa4597
      Randy Dunlap authored 
      

When NETCONSOLE_DYNAMIC=y and CONFIGFS_FS=m, there are build errors
in netconsole:

drivers/built-in.o: In function `drop_netconsole_target':
netconsole.c:(.text+0x1a100f): undefined reference to `config_item_put'
drivers/built-in.o: In function `make_netconsole_target':
netconsole.c:(.text+0x1a10b9): undefined reference to `config_item_init_type_name'
drivers/built-in.o: In function `write_msg':
netconsole.c:(.text+0x1a11a4): undefined reference to `config_item_get'
netconsole.c:(.text+0x1a1211): undefined reference to `config_item_put'
drivers/built-in.o: In function `netconsole_netdev_event':
netconsole.c:(.text+0x1a12cc): undefined reference to `config_item_put'
netconsole.c:(.text+0x1a12ec): undefined reference to `config_item_get'
netconsole.c:(.text+0x1a1366): undefined reference to `config_item_put'
drivers/built-in.o: In function `init_netconsole':
netconsole.c:(.init.text+0x953a): undefined reference to `config_group_init'
netconsole.c:(.init.text+0x9560): undefined reference to `configfs_register_subsystem'
drivers/built-in.o: In function `dynamic_netconsole_exit':
netconsole.c:(.exit.text+0x809): undefined reference to `configfs_unregister_subsystem'

so fix the NETCONSOLE_DYNAMIC depends clause to prevent this.
Based on email suggestion from Ben Hutchings.  Thanks.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=37992

Reported-by: default avatarDavid Hill <hilld@binarystorm.net>
Signed-off-by: default avatarRandy Dunlap <randy.dunlap@oracle.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      58fa4597
  11. Jun 21, 2011
  13. Jun 20, 2011