This issue was discovered during a code audit.
After cancel_work_sync() is called from espintcp_close(),
espintcp_tx_work() can still be scheduled from paths such as
the Delayed ACK handler or ksoftirqd.
As a result, the espintcp_tx_work() worker may dereference a
freed espintcp ctx or sk.
The following is a simple race scenario:
cpu0 cpu1
espintcp_close()
cancel_work_sync(&ctx->work);
espintcp_write_space()
schedule_work(&ctx->work);
To prevent this race condition, cancel_work_sync() is
replaced with disable_work_sync().
Fixes: e27cca96cd ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/aZSie7rEdh9Nu0eM@v4bel
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
e1512c1db9