This patch adds basic handling of PERF_RECORD_BPF_EVENT. Tracking of
PERF_RECORD_BPF_EVENT is OFF by default. Option --bpf-event is added to
turn it on.
Committer notes:
Add dummy machine__process_bpf_event() variant that returns zero for
systems without HAVE_LIBBPF_SUPPORT, such as Alpine Linux, unbreaking
the build in such systems.
Remove the needless include <machine.h> from bpf->event.h, provide just
forward declarations for the structs and unions in the parameters, to
reduce compilation time and needless rebuilds when machine.h gets
changed.
Committer testing:
When running with:
# perf record --bpf-event
On an older kernel where PERF_RECORD_BPF_EVENT and PERF_RECORD_KSYMBOL
is not present, we fallback to removing those two bits from
perf_event_attr, making the tool to continue to work on older kernels:
perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
ksymbol 1
bpf_event 1
------------------------------------------------------------
sys_perf_event_open: pid 5779 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off bpf_event
------------------------------------------------------------
perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
ksymbol 1
------------------------------------------------------------
sys_perf_event_open: pid 5779 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off ksymbol
------------------------------------------------------------
perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
------------------------------------------------------------
And then proceeds to work without those two features.
As passing --bpf-event is an explicit action performed by the user, perhaps we
should emit a warning telling that the kernel has no such feature, but this can
be done on top of this patch.
Now with a kernel that supports these events, start the 'record --bpf-event -a'
and then run 'perf trace sleep 10000' that will use the BPF
augmented_raw_syscalls.o prebuilt (for another kernel version even) and thus
should generate PERF_RECORD_BPF_EVENT events:
[root@quaco ~]# perf record -e dummy -a --bpf-event
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.713 MB perf.data ]
[root@quaco ~]# bpftool prog
13: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 13,14
14: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 13,14
15: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 15,16
16: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 15,16
17: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:44-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 17,18
18: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:44-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 17,18
21: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:45-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 21,22
22: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:45-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 21,22
31: tracepoint name sys_enter tag 12504ba9402f952f gpl
loaded_at 2019-01-19T09:19:56-0300 uid 0
xlated 512B jited 374B memlock 4096B map_ids 30,29,28
32: tracepoint name sys_exit tag c1bd85c092d6e4aa gpl
loaded_at 2019-01-19T09:19:56-0300 uid 0
xlated 256B jited 191B memlock 4096B map_ids 30,29
# perf report -D | grep PERF_RECORD_BPF_EVENT | nl
1 0 55834574849 0x4fc8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 13
2 0 60129542145 0x5118 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 14
3 0 64424509441 0x5268 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 15
4 0 68719476737 0x53b8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 16
5 0 73014444033 0x5508 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 17
6 0 77309411329 0x5658 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 18
7 0 90194313217 0x57a8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 21
8 0 94489280513 0x58f8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 22
9 7 620922484360 0xb6390 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 29
10 7 620922486018 0xb6410 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 29
11 7 620922579199 0xb6490 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 30
12 7 620922580240 0xb6510 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 30
13 7 620922765207 0xb6598 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 31
14 7 620922874543 0xb6620 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 32
#
There, the 31 and 32 tracepoint BPF programs put in place by 'perf trace'.
Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-7-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch handles PERF_RECORD_KSYMBOL in perf record/report.
Specifically, map and symbol are created for ksymbol register, and
removed for ksymbol unregister.
This patch also sets perf_event_attr.ksymbol properly. The flag is ON by
default.
Committer notes:
Use proper inttypes.h for u64, fixing the build in some environments
like in the android NDK r15c targetting ARM 32-bit.
I.e. fixing this build error:
util/event.c: In function 'perf_event__fprintf_ksymbol':
util/event.c:1489:10: error: format '%lx' expects argument of type 'long unsigned int', but argument 3 has type 'u64' [-Werror=format=]
event->ksymbol_event.flags, event->ksymbol_event.name);
^
cc1: all warnings being treated as errors
Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-6-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For better performance analysis of BPF programs, this patch introduces
PERF_RECORD_BPF_EVENT, a new perf_event_type that exposes BPF program
load/unload information to user space.
Each BPF program may contain up to BPF_MAX_SUBPROGS (256) sub programs.
The following example shows kernel symbols for a BPF program with 7 sub
programs:
ffffffffa0257cf9 t bpf_prog_b07ccb89267cf242_F
ffffffffa02592e1 t bpf_prog_2dcecc18072623fc_F
ffffffffa025b0e9 t bpf_prog_bb7a405ebaec5d5c_F
ffffffffa025dd2c t bpf_prog_a7540d4a39ec1fc7_F
ffffffffa025fcca t bpf_prog_05762d4ade0e3737_F
ffffffffa026108f t bpf_prog_db4bd11e35df90d4_F
ffffffffa0263f00 t bpf_prog_89d64e4abf0f0126_F
ffffffffa0257cf9 t bpf_prog_ae31629322c4b018__dummy_tracepoi
When a bpf program is loaded, PERF_RECORD_KSYMBOL is generated for each
of these sub programs. Therefore, PERF_RECORD_BPF_EVENT is not needed
for simple profiling.
For annotation, user space need to listen to PERF_RECORD_BPF_EVENT and
gather more information about these (sub) programs via sys_bpf.
Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradeaed.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-4-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For the original mode of operation it isn't needed, since we report back
errors via PERF_RECORD_LOST records in the ring buffer, but for use in
bpf_perf_event_output() it is convenient to return the errors, basically
-ENOSPC.
Currently bpf_perf_event_output() returns an error indication, the last
thing it does, which is to push it to the ring buffer is that can fail
and if so, this failure won't be reported back to its users, fix it.
Reported-by: Jamal Hadi Salim <jhs@mojatatu.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20190118150938.GN5823@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for the new s390 PMU device cpum_cf_diag to extract the
counter set diagnostic data. This data is available as event raw data
and can be created with this command:
[root@s35lp76 perf]# ./perf record -R -e '{rbd000,rbc000}' --
~/mytests/facultaet 2500
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.009 MB perf.data ]
[root@s35lp76 perf]#
The new event 0xbc000 generated this counter set diagnostic trace data.
The data can be extracted using command:
[root@s35lp76 perf]# ./perf report --stdio --itrace=d
#
# Total Lost Samples: 0
#
# Samples: 21 of events 'anon group { rbd000, rbc000 }'
# Event count (approx.): 21
#
# Overhead Command Shared Object Symbol
# ................ ......... ................. ........................
#
80.95% 0.00% facultaet facultaet [.] facultaet
4.76% 0.00% facultaet [kernel.kallsyms] [k] check_chain_key
4.76% 0.00% facultaet [kernel.kallsyms] [k] ftrace_likely_update
4.76% 0.00% facultaet [kernel.kallsyms] [k] lock_release
4.76% 0.00% facultaet libc-2.26.so [.] _dl_addr
[root@s35lp76 perf]# ll aux*
-rw-r--r-- 1 root root 3408 Oct 16 12:40 aux.ctr.02
-rw-r--r-- 1 root root 4096 Oct 16 12:40 aux.smp.02
[root@s35lp76 perf]#
The files named aux.ctr.## contain the counter set diagnostic data and
the files named aux.smp.## contain the sampling diagnostic data. ##
stand for the CPU number the data was taken from.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20190117093003.96287-4-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On s390 the event bc000 (also named CF_DIAG) extracts the CPU
Measurement Facility diagnostic counter sets and displays them as
counter number and counter value pairs sorted by counter set number.
Output:
[root@s35lp76 perf]# ./perf report -D --stdio
[00000000] Counterset:0 Counters:6
Counter:000 Value:0x000000000085ec36 Counter:001 Value:0x0000000000796c94
Counter:002 Value:0x0000000000005ada Counter:003 Value:0x0000000000092460
Counter:004 Value:0x0000000000006073 Counter:005 Value:0x00000000001a9a73
[0x000038] Counterset:1 Counters:2
Counter:000 Value:0x000000000007c59f Counter:001 Value:0x000000000002fad6
[0x000050] Counterset:2 Counters:16
Counter:000 Value:000000000000000000 Counter:001 Value:000000000000000000
Counter:002 Value:000000000000000000 Counter:003 Value:000000000000000000
Counter:004 Value:000000000000000000 Counter:005 Value:000000000000000000
Counter:006 Value:000000000000000000 Counter:007 Value:000000000000000000
Counter:008 Value:000000000000000000 Counter:009 Value:000000000000000000
Counter:010 Value:000000000000000000 Counter:011 Value:000000000000000000
Counter:012 Value:000000000000000000 Counter:013 Value:000000000000000000
Counter:014 Value:000000000000000000 Counter:015 Value:000000000000000000
[0x0000d8] Counterset:3 Counters:128
Counter:000 Value:0x000000000000020f Counter:001 Value:0x00000000000001d8
Counter:002 Value:0x000000000000d7fa Counter:003 Value:0x000000000000008b
...
The number in brackets is the offset into the raw data field of the
sample.
New functions trace_event_sample_raw__init() and s390_sample_raw() are
introduced in the code path to enable interpretation on non s390
platforms. This event bc000 attached raw data is generated only on s390
platform. Correct display on other platforms requires correct endianness
handling.
Committer notes:
Added a init function that sets up a evlist function pointer to avoid
repeated tests on evlist->env and calls to perf_env__name() that
involves normalizing, etc, for each PERF_RECORD_SAMPLE.
Removed needless __maybe_unused from the trace_event_raw()
prototype in session.h, move it to be an static function in evlist.
The 'offset' variable is a size_t, not an u64, fix it to avoid this on
some arches:
CC /tmp/build/perf/util/s390-sample-raw.o
util/s390-sample-raw.c: In function 's390_cpumcfdg_testctr':
util/s390-sample-raw.c:77:4: error: format '%llx' expects argument of type 'long long unsigned int', but argument 4 has type 'size_t' [-Werror=format=]
pr_err("Invalid counter set entry at %#" PRIx64 "\n",
^
cc1: all warnings being treated as errors
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Link: https://lkml.kernel.org/r/9c856ac0-ef23-72b5-901d-a1f815508976@linux.ibm.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: https://lkml.kernel.org/n/tip-s3jhif06et9ug78qhclw41z1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull rdma fixes frfom Jason Gunthorpe:
"Not much so far. We have the usual batch of bugs and two fixes to code
merged this cycle:
- Restore valgrind support for the ioctl verbs interface merged this
window, and fix a missed error code on an error path from that
conversion
- A user reported crash on obsolete mthca hardware
- pvrdma was using the wrong command opcode toward the hypervisor
- NULL pointer crash regression when dumping rdma-cm over netlink
- Be conservative about exposing the global rkey"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
RDMA/uverbs: Mark ioctl responses with UVERBS_ATTR_F_VALID_OUTPUT
RDMA/mthca: Clear QP objects during their allocation
RDMA/vmw_pvrdma: Return the correct opcode when creating WR
RDMA/cma: Add cm_id restrack resource based on kernel or user cm_id type
RDMA/nldev: Don't expose unsafe global rkey to regular user
RDMA/uverbs: Fix post send success return value in case of error
Pull drm fixes from Dave Airlie:
"The rc3 fixes are a bit scattered:
- meson, sun4i and rockchip all had missing of_node_put.
- qxl and virtio both were advertising dma-buf to userspace when they
really shouldn't have.
Otherwise:
meson:
- modesetting regression fix
i915 GVT:
- one cmd parser failure fix
- region cleanup fix in vGPU destroy
amdgpu:
- KFD fixes for arm64 mixed APU/DGPU
- vega12 powerplay fix
- raven DC fixes
- freesync fix"
* tag 'drm-fixes-2019-01-18' of git://anongit.freedesktop.org/drm/drm:
drm/amd/display: Detach backlight from stream
drm/sun4i: backend: add missing of_node_puts
Revert "drm/amdgpu: validate user pitch alignment"
Revert "drm/amdgpu: validate user GEM object size"
drm/meson: Fix atomic mode switching regression
drm/i915/gvt: Fix mmap range check
drm/i915/gvt: free VFIO region space in vgpu detach
drm/amd/display: Fix disabled cursor on top screen edge
drm/amd/display: fix warning on raven hotplug
drm/amd/display: fix PME notification not working in RV desktop
drm/amd/display: Only get the connector state for VRR when toggled
drm/amd/display: Pack DMCU iRAM alignment
drm/amd/powerplay: run acg btc for Vega12
drm/amdkfd: Don't assign dGPUs to APU topology devices
drm/amdkfd: Allow building KFD on ARM64 (v2)
drm/meson: add missing of_node_put
drm/virtio: drop prime import/export callbacks
drm/qxl: drop prime import/export callbacks
drm/i915/gvt: Allow F_CMD_ACCESS on mmio 0x21f0
drm/rockchip: add missing of_node_put
Pull LED fix from Jacek Anaszewski.
* tag 'led-fix-for-5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
leds: lp5523: fix a missing check of return value of lp55xx_read
Pull hwmon fixes from Guenter Roeck:
"Minor fixes/regressions"
* tag 'hwmon-for-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (tmp421) Correct the misspelling of the tmp442 compatible attribute in OF device ID table
hwmon: (occ) Fix potential integer overflow
hwmon: (lm80) Fix missing unlock on error in set_fan_div()
hwmon: (nct6775) Enable IO mapping for NCT6797D and NCT6798D
hwmon: (nct6775) Fix chip ID for NCT6798D
When lp55xx_read() fails, "status" is an uninitialized variable and thus
may contain random value; using it leads to undefined behaviors.
The fix inserts a check for the return value of lp55xx_read: if it
fails, returns with its error code.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Pull AFS fixes from David Howells:
"Here's a set of fixes for AFS:
- Use struct_size() for kzalloc() size calculation.
- When calling YFS.CreateFile rather than AFS.CreateFile, it is
possible to create a file with a file lock already held. The
default value indicating no lock required is actually -1, not 0.
- Fix an oops in inode/vnode validation if the target inode doesn't
have a server interest assigned (ie. a server that will notify us
of changes by third parties).
- Fix refcounting of keys in file locking.
- Fix a race in refcounting asynchronous operations in the event of
an error during request transmission. The provision of a dedicated
function to get an extra ref on a call is split into a separate
commit"
* tag 'afs-fixes-20190117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
afs: Fix race in async call refcounting
afs: Provide a function to get a ref on a call
afs: Fix key refcounting in file locking code
afs: Don't set vnode->cb_s_break in afs_validate()
afs: Set correct lock type for the yfs CreateFile
afs: Use struct_size() in kzalloc()
Pull swiotlb fix from Konrad Rzeszutek Wilk:
"A tiny fix for v5.0-rc2:
This fixes an issue with GPU cards not working anymore with the DMA
mapping work Christopher did - as the SWIOTLB is initialized first and
then free'd (as IOMMU is available) but we forgot to clear our start
and end entries which are used and BOOM"
* 'stable/for-linus-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit
There's a race between afs_make_call() and afs_wake_up_async_call() in the
case that an error is returned from rxrpc_kernel_send_data() after it has
queued the final packet.
afs_make_call() will try and clean up the mess, but the call state may have
been moved on thereby causing afs_process_async_call() to also try and to
delete the call.
Fix this by:
(1) Getting an extra ref for an asynchronous call for the call itself to
hold. This makes sure the call doesn't evaporate on us accidentally
and will allow the call to be retained by the caller in a future
patch. The ref is released on leaving afs_make_call() or
afs_wait_for_call_to_complete().
(2) In the event of an error from rxrpc_kernel_send_data():
(a) Don't set the call state to AFS_CALL_COMPLETE until *after* the
call has been aborted and ended. This prevents
afs_deliver_to_call() from doing anything with any notifications
it gets.
(b) Explicitly end the call immediately to prevent further callbacks.
(c) Cancel any queued async_work and wait for the work if it's
executing. This allows us to be sure the race won't recur when we
change the state. We put the work queue's ref on the call if we
managed to cancel it.
(d) Put the call's ref that we got in (1). This belongs to us as long
as the call is in state AFS_CALL_CL_REQUESTING.
Fixes: 341f741f04 ("afs: Refcount the afs_call struct")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the refcounting of the authentication keys in the file locking code.
The vnode->lock_key member points to a key on which it expects to be
holding a ref, but it isn't always given an extra ref, however.
Fixes: 0fafdc9f88 ("afs: Fix file locking")
Signed-off-by: David Howells <dhowells@redhat.com>
A cb_interest record is not necessarily attached to the vnode on entry to
afs_validate(), which can cause an oops when we try to bring the vnode's
cb_s_break up to date in the default case (ie. no current callback promise
and the vnode has not been deleted).
Fix this by simply removing the line, as vnode->cb_s_break will be set when
needed by afs_register_server_cb_interest() when we next get a callback
promise from RPC call.
The oops looks something like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
...
RIP: 0010:afs_validate+0x66/0x250 [kafs]
...
Call Trace:
afs_d_revalidate+0x8d/0x340 [kafs]
? __d_lookup+0x61/0x150
lookup_dcache+0x44/0x70
? lookup_dcache+0x44/0x70
__lookup_hash+0x24/0xa0
do_unlinkat+0x11d/0x2c0
__x64_sys_unlink+0x23/0x30
do_syscall_64+0x4d/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: ae3b7361dc ("afs: Fix validation/callback interaction")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
