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| author | Peter Zijlstra <peterz@infradead.org> | 2018-10-11 12:38:27 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 07:41:43 -0800 |
| commit | 74ede0af32f565ac5b7222c8722cc7da6951bef4 (patch) | |
| tree | 25975cb900c821f438d5afdd65b5ab63e9abc237 /kernel | |
| parent | 4a2b54a750bf18be02997944464396485b7ef284 (diff) | |
| download | linux-stable-74ede0af32f565ac5b7222c8722cc7da6951bef4.tar.gz linux-stable-74ede0af32f565ac5b7222c8722cc7da6951bef4.tar.bz2 linux-stable-74ede0af32f565ac5b7222c8722cc7da6951bef4.zip | |
x86/percpu: Fix this_cpu_read()
commit b59167ac7bafd804c91e49ad53c6d33a7394d4c8 upstream.
Eric reported that a sequence count loop using this_cpu_read() got
optimized out. This is wrong, this_cpu_read() must imply READ_ONCE()
because the interface is IRQ-safe, therefore an interrupt can have
changed the per-cpu value.
Fixes: 7c3576d261ce ("[PATCH] i386: Convert PDA into the percpu section")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Cc: hpa@zytor.com
Cc: eric.dumazet@gmail.com
Cc: bp@alien8.de
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181011104019.748208519@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions