Thanks for reporting. This issue has been fixed by the below commit in
bpf-next repo, which is waiting to be pulled into net-next.
=====
commit 2310035fa03f651dd5b03f19a26a97512aa8842c
Author: Yonghong Song <y...@fb.com>
Date: Mon Jan 22 22:53:51 2018 -0800
bpf: fix incorrect kmalloc usage in lpm_trie MAP_GET_NEXT_KEY rcu
region
In commit b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command
for LPM_TRIE map"),
the implemented MAP_GET_NEXT_KEY callback function is guarded with
rcu read lock.
In the function body, "kmalloc(size, GFP_USER | __GFP_NOWARN)" is
used which may
sleep and violate rcu read lock region requirements. This patch
fixed the issue
by using GFP_ATOMIC instead to avoid blocking kmalloc. Tested with
CONFIG_DEBUG_ATOMIC_SLEEP=y as suggested by Eric Dumazet.
Fixes: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for
LPM_TRIE map")
Signed-off-by: Yonghong Song <y...@fb.com>
Reported-by: syzbot <syzkal...@googlegroups.com>
Reviewed-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
======
Thanks!
On 1/27/18 12:04 AM, kernel test robot wrote:
FYI, we noticed the following commit (built with gcc-7):
commit: 8c417dc15f9522672795981dcb63d9099ca6bd8c ("tools/bpf: add a testcase for
MAP_GET_NEXT_KEY command of LPM_TRIE map")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
in testcase: kernel_selftests
with following parameters:
test-description: The kernel contains a set of "self tests" under the
tools/testing/selftests/ directory. These are intended to be small unit tests to exercise
individual code paths in the kernel.
test-url: https://www.kernel.org/doc/Documentation/kselftest.txt
on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 4G
caused below changes (please refer to attached dmesg/kmsg for entire
log/backtrace):
+---------------------------------------------------------------------+------------+------------+
| |
b471f2f1de | 8c417dc15f |
+---------------------------------------------------------------------+------------+------------+
| boot_successes | 0
| 0 |
| boot_failures | 8
| 8 |
| invoked_oom-killer:gfp_mask=0x | 4
| 4 |
| Mem-Info | 4
| 4 |
| Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 4
| 4 |
| BUG:sleeping_function_called_from_invalid_context_at_lib/usercopy.c | 4
| |
| BUG:sleeping_function_called_from_invalid_context_at_mm/slab.h | 0
| 4 |
+---------------------------------------------------------------------+------------+------------+
[ 275.143042] BUG: sleeping function called from invalid context at
mm/slab.h:419
[ 275.146347] in_atomic(): 1, irqs_disabled(): 0, pid: 7020, name: test_lpm_map
[ 275.148889] CPU: 0 PID: 7020 Comm: test_lpm_map Not tainted
4.15.0-rc8-01647-g8c417dc #1
[ 275.151961] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.10.2-1 04/01/2014
[ 275.155015] Call Trace:
[ 275.156181] dump_stack+0x5c/0x7b
[ 275.157563] ___might_sleep+0xf1/0x110
[ 275.159078] __kmalloc+0x178/0x210
[ 275.160459] trie_get_next_key+0x57/0x2a0
[ 275.162019] ? _cond_resched+0x19/0x30
[ 275.163494] ? __kmalloc+0x17d/0x210
[ 275.165010] SyS_bpf+0xdbb/0x14b0
[ 275.166359] ? _cond_resched+0x19/0x30
[ 275.167851] entry_SYSCALL_64_fastpath+0x20/0x83
[ 275.169616] RIP: 0033:0x7fce862efe19
[ 275.171053] RSP: 002b:00007ffccbb62668 EFLAGS: 00000202
[ 275.183028] test_lpm: OK
[ 275.184984]
[ 275.188333] ok 1..5 selftests: test_lpm_map [PASS]
[ 275.188338]
[ 275.191610] selftests: test_progs
[ 275.191615]
[ 275.208854] ========================================
[ 275.208859]
[ 275.731322] libbpf: incorrect bpf_call opcode
[ 275.731329]
[ 275.739681] libbpf: incorrect bpf_call opcode
[ 275.739687]
[ 275.768456] test_pkt_access:PASS:ipv4 165 nsec
[ 275.768463]
[ 275.775864] test_pkt_access:PASS:ipv6 162 nsec
[ 275.775869]
[ 275.783113] test_xdp:PASS:ipv4 4283 nsec
[ 275.783251]
[ 275.798987] test_xdp:PASS:ipv6 1919 nsec
[ 275.798992]
[ 275.811095] test_l4lb:PASS:ipv4 1860 nsec
[ 275.811248]
[ 275.820459] test_l4lb:PASS:ipv6 3139 nsec
[ 275.820464]
[ 275.825614] test_tcp_estats:PASS: 0 nsec
[ 275.825618]
[ 275.831543] test_bpf_obj_id:PASS:get-fd-by-notexist-prog-id 0 nsec
[ 275.831548]
[ 275.838707] test_bpf_obj_id:PASS:get-fd-by-notexist-map-id 0 nsec
[ 275.838712]
[ 275.845485] test_bpf_obj_id:PASS:get-map-info(fd) 0 nsec
[ 275.845490]
[ 275.851833] test_bpf_obj_id:PASS:get-prog-info(fd) 0 nsec
[ 275.851838]
[ 275.858121] test_bpf_obj_id:PASS:get-map-info(fd) 0 nsec
[ 275.858126]
[ 275.862282] test_bpf_obj_id:PASS:get-prog-info(fd) 0 nsec
[ 275.862286]
[ 275.866722] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.866726]
[ 275.871573] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.871577]
[ 275.876121] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.876125]
[ 275.880766] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.880769]
[ 275.885053] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.885057]
[ 275.889288] test_bpf_obj_id:PASS:get-prog-fd-bad-nr-map-ids 0 nsec
[ 275.889291]
[ 275.894180] test_bpf_obj_id:PASS:get-prog-info(next_id->fd) 0 nsec
[ 275.894184]
[ 275.900509] test_bpf_obj_id:PASS:get-prog-fd(next_id) 0 nsec
[ 275.900513]
[ 275.905233] test_bpf_obj_id:PASS:get-prog-fd-bad-nr-map-ids 0 nsec
[ 275.905236]
[ 275.910550] test_bpf_obj_id:PASS:get-prog-info(next_id->fd) 0 nsec
[ 275.910554]
[ 275.917881] test_bpf_obj_id:PASS:check total prog id found by get_next_id 0
nsec
[ 275.917885]
[ 275.926199] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.926205]
[ 275.932417] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.932422]
[ 275.937351] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.937356]
[ 275.942885] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.942891]
[ 275.947970] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.947975]
[ 275.953278] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.953283]
[ 275.958715] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.958720]
[ 275.963666] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.963671]
[ 275.968511] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.968516]
[ 275.973634] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.973639]
[ 275.979036] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
[ 275.979041]
[ 275.984546] test_bpf_obj_id:PASS:check get-map-info(next_id->fd) 0 nsec
[ 275.984551]
[ 275.990201] test_bpf_obj_id:PASS:get-map-fd(next_id) 0 nsec
To reproduce:
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this
email
Thanks,
Xiaolong
