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[ Upstream commit d1f20c03f48102e52eb98b8651d129b83134cae4 ]
hb_timer might not start at all for a particular transport because its
start is conditional. In a result a node is not sending heartbeats.
Function sctp_transport_reset_hb_timer has two roles:
- initial start of hb_timer for a given transport,
- update expire date of hb_timer for a given transport.
The function is optimized to update timer's expire only if it is before
a new calculated one but this comparison is invalid for a timer which
has not yet started. Such a timer has expire == 0 and if a new expire
value is bigger than (MAX_JIFFIES / 2 + 2) then "time_before" macro will
fail and timer will not start resulting in no heartbeat packets send by
the node.
This was found when association was initialized within first 5 mins
after system boot due to jiffies init value which is near to MAX_JIFFIES.
Test kernel version: 4.9.154 (ARCH=arm)
hb_timer.expire = 0; //initialized, not started timer
new_expire = MAX_JIFFIES / 2 + 2; //or more
time_before(hb_timer.expire, new_expire) == false
Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often")
Reported-by: Marcin Stojek <marcin.stojek@nokia.com>
Tested-by: Marcin Stojek <marcin.stojek@nokia.com>
Signed-off-by: Maciej Kwiecien <maciej.kwiecien@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.