Daniel Borkmann a64af0ef1c bpf, libbpf: use correct barriers in perf ring buffer walk ... Given libbpf is a generic library and not restricted to x86-64 only, the compiler barrier in bpf_perf_event_read_simple() after fetching the head needs to be replaced with smp_rmb() at minimum. Also, writing out the tail we should use WRITE_ONCE() to avoid store tearing. Now that we have the logic in place in ring_buffer_read_head() and ring_buffer_write_tail() helper also used by perf tool which would select the correct and best variant for a given architecture (e.g. x86-64 can avoid CPU barriers entirely), make use of these in order to fix bpf_perf_event_read_simple(). Fixes: d0cabbb021 ("tools: bpf: move the event reading loop to libbpf") Fixes: 39111695b1 ("samples: bpf: add bpf_perf_event_output example") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>		2018-10-19 13:43:08 -07:00
..
accounting
arch	tools, perf: add and use optimized ring_buffer_{read_head, write_tail} helpers	2018-10-19 13:43:08 -07:00
bpf	tools: bpftool: use 4 context mode for the NFP disasm	2018-10-18 22:16:02 +02:00
build	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2018-08-15 15:04:25 -07:00
cgroup
firewire
gpio
hv	tools: hv: fcopy: set 'error' in case an unknown operation was requested	2018-09-30 08:49:55 -07:00
iio	iio: Add modifier for DUV light	2018-07-23 19:18:10 +01:00
include	tools, perf: add and use optimized ring_buffer_{read_head, write_tail} helpers	2018-10-19 13:43:08 -07:00
kvm/kvm_stat	tools/kvm_stat: cut down decimal places in update interval dialog	2018-10-01 15:40:59 +02:00
laptop
leds
lib	bpf, libbpf: use correct barriers in perf ring buffer walk	2018-10-19 13:43:08 -07:00
memory-model	tools/memory-model: Rename litmus tests to comply to norm7	2018-07-17 09:30:36 +02:00
nfsd
objtool	Kbuild updates for v4.19	2018-08-15 12:09:03 -07:00
pci	tools: PCI: Add MSI-X support	2018-07-19 11:47:13 +01:00
pcmcia
perf	tools, perf: add and use optimized ring_buffer_{read_head, write_tail} helpers	2018-10-19 13:43:08 -07:00
power	treewide: convert ISO_8859-1 text comments to utf-8	2018-08-23 18:48:43 -07:00
scripts
spi
testing	selftests/bpf: add missing executables to .gitignore	2018-10-19 13:31:27 -07:00
thermal/tmon
time
usb	tools: usb: ffs-test: Fix build on big endian systems	2018-07-17 10:12:51 +03:00
virtio	tools/virtio: add kmalloc_array stub	2018-07-27 16:54:40 +03:00
vm	tools/vm/page-types.c: fix "defined but not used" warning	2018-09-04 16:45:02 -07:00
wmi
Makefile