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Eric Dumazet
72bf4f1767
Under memory stress conditions, tcp_sendmsg_locked()
might call sk_stream_wait_memory(), thus releasing the socket lock.
If a fresh skb has been allocated prior to this,
we should not leave it in the write queue otherwise
tcp_write_xmit() could panic.
This apparently does not happen often, but a future change
in __sk_mem_raise_allocated() that Shakeel and others are
considering would increase chances of being hurt.
Under discussion is to remove this controversial part:
/* Fail only if socket is _under_ its sndbuf.
* In this case we cannot block, so that we have to fail.
*/
if (sk->sk_wmem_queued + size >= sk->sk_sndbuf) {
/* Force charge with __GFP_NOFAIL */
if (memcg_charge && !charged) {
mem_cgroup_charge_skmem(sk->sk_memcg, amt,
gfp_memcg_charge() | __GFP_NOFAIL);
}
return 1;
}
Fixes: fdfc5c8594 ("tcp: remove empty skb from write queue in error cases")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Link: https://lore.kernel.org/r/20231019112457.1190114-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.