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author | Will Deacon <will.deacon@arm.com> | 2019-04-08 14:23:17 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-10 17:53:15 +0200 |
commit | d5d05286b6ba27ff4b29f9bf2ba99c716a31c307 (patch) | |
tree | ff4b3848ad3fb24a27fc30199e47a49056697f1c /net/sched/act_police.c | |
parent | d2045151af9da38178c6e38581d94f239dc840e5 (diff) |
arm64: futex: Bound number of LDXR/STXR loops in FUTEX_WAKE_OP
commit 03110a5cb2161690ae5ac04994d47ed0cd6cef75 upstream.
Our futex implementation makes use of LDXR/STXR loops to perform atomic
updates to user memory from atomic context. This can lead to latency
problems if we end up spinning around the LL/SC sequence at the expense
of doing something useful.
Rework our futex atomic operations so that we return -EAGAIN if we fail
to update the futex word after 128 attempts. The core futex code will
reschedule if necessary and we'll try again later.
Cc: <stable@kernel.org>
Fixes: 6170a97460db ("arm64: Atomic operations")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sched/act_police.c')
0 files changed, 0 insertions, 0 deletions