From: Sasha Levin <sashal@kernel•org>
To: linux-kernel@vger•kernel.org, stable@vger•kernel.org
Cc: Yonghong Song <yhs@fb•com>,
Daniel Borkmann <daniel@iogearbox•net>,
Song Liu <songliubraving@fb•com>, Sasha Levin <sashal@kernel•org>,
linux-kselftest@vger•kernel.org, netdev@vger•kernel.org,
bpf@vger•kernel.org, clang-built-linux@googlegroups•com
Subject: [PATCH AUTOSEL 5.4 267/350] bpf, testing: Workaround a verifier failure for test_progs
Date: Tue, 10 Dec 2019 16:06:12 -0500 [thread overview]
Message-ID: <20191210210735.9077-228-sashal@kernel.org> (raw)
In-Reply-To: <20191210210735.9077-1-sashal@kernel.org>
From: Yonghong Song <yhs@fb•com>
[ Upstream commit b7a0d65d80a0c5034b366392624397a0915b7556 ]
With latest llvm compiler, running test_progs will have the following
verifier failure for test_sysctl_loop1.o:
libbpf: load bpf program failed: Permission denied
libbpf: -- BEGIN DUMP LOG ---
libbpf:
invalid indirect read from stack var_off (0x0; 0xff)+196 size 7
...
libbpf: -- END LOG --
libbpf: failed to load program 'cgroup/sysctl'
libbpf: failed to load object 'test_sysctl_loop1.o'
The related bytecode looks as below:
0000000000000308 LBB0_8:
97: r4 = r10
98: r4 += -288
99: r4 += r7
100: w8 &= 255
101: r1 = r10
102: r1 += -488
103: r1 += r8
104: r2 = 7
105: r3 = 0
106: call 106
107: w1 = w0
108: w1 += -1
109: if w1 > 6 goto -24 <LBB0_5>
110: w0 += w8
111: r7 += 8
112: w8 = w0
113: if r7 != 224 goto -17 <LBB0_8>
And source code:
for (i = 0; i < ARRAY_SIZE(tcp_mem); ++i) {
ret = bpf_strtoul(value + off, MAX_ULONG_STR_LEN, 0,
tcp_mem + i);
if (ret <= 0 || ret > MAX_ULONG_STR_LEN)
return 0;
off += ret & MAX_ULONG_STR_LEN;
}
Current verifier is not able to conclude that register w0 before '+'
at insn 110 has a range of 1 to 7 and thinks it is from 0 - 255. This
leads to more conservative range for w8 at insn 112, and later verifier
complaint.
Let us workaround this issue until we found a compiler and/or verifier
solution. The workaround in this patch is to make variable 'ret' volatile,
which will force a reload and then '&' operation to ensure better value
range. With this patch, I got the below byte code for the loop:
0000000000000328 LBB0_9:
101: r4 = r10
102: r4 += -288
103: r4 += r7
104: w8 &= 255
105: r1 = r10
106: r1 += -488
107: r1 += r8
108: r2 = 7
109: r3 = 0
110: call 106
111: *(u32 *)(r10 - 64) = r0
112: r1 = *(u32 *)(r10 - 64)
113: if w1 s< 1 goto -28 <LBB0_5>
114: r1 = *(u32 *)(r10 - 64)
115: if w1 s> 7 goto -30 <LBB0_5>
116: r1 = *(u32 *)(r10 - 64)
117: w1 &= 7
118: w1 += w8
119: r7 += 8
120: w8 = w1
121: if r7 != 224 goto -21 <LBB0_9>
Insn 117 did the '&' operation and we got more precise value range
for 'w8' at insn 120. The test is happy then:
#3/17 test_sysctl_loop1.o:OK
Signed-off-by: Yonghong Song <yhs@fb•com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox•net>
Acked-by: Song Liu <songliubraving@fb•com>
Link: https://lore.kernel.org/bpf/20191107170045.2503480-1-yhs@fb.com
Signed-off-by: Sasha Levin <sashal@kernel•org>
---
tools/testing/selftests/bpf/progs/test_sysctl_loop1.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/progs/test_sysctl_loop1.c b/tools/testing/selftests/bpf/progs/test_sysctl_loop1.c
index 608a06871572d..d22e438198cf7 100644
--- a/tools/testing/selftests/bpf/progs/test_sysctl_loop1.c
+++ b/tools/testing/selftests/bpf/progs/test_sysctl_loop1.c
@@ -44,7 +44,10 @@ int sysctl_tcp_mem(struct bpf_sysctl *ctx)
unsigned long tcp_mem[TCP_MEM_LOOPS] = {};
char value[MAX_VALUE_STR_LEN];
unsigned char i, off = 0;
- int ret;
+ /* a workaround to prevent compiler from generating
+ * codes verifier cannot handle yet.
+ */
+ volatile int ret;
if (ctx->write)
return 0;
--
2.20.1
next prev parent reply other threads:[~2019-12-10 21:19 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191210210735.9077-1-sashal@kernel.org>
2019-12-10 21:02 ` [PATCH AUTOSEL 5.4 048/350] ath10k: fix offchannel tx failure when no ath10k_mac_tx_frm_has_freq Sasha Levin
2019-12-10 21:02 ` [PATCH AUTOSEL 5.4 056/350] selftests/bpf: Correct path to include msg + path Sasha Levin
2019-12-10 21:02 ` [PATCH AUTOSEL 5.4 059/350] rtw88: fix NSS of hw_cap Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 077/350] mwifiex: pcie: Fix memory leak in mwifiex_pcie_init_evt_ring Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 079/350] selftests/bpf: Fix btf_dump padding test case Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 080/350] libbpf: Fix struct end padding in btf_dump Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 081/350] libbpf: Fix passing uninitialized bytes to setsockopt Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 082/350] net/smc: increase device refcount for added link group Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 083/350] team: call RCU read lock when walking the port_list Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 106/350] ath10k: Correct error handling of dma_map_single() Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 107/350] rtw88: coex: Set 4 slot mode for A2DP Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 119/350] Bluetooth: missed cpu_to_le16 conversion in hci_init4_req Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 120/350] Bluetooth: Workaround directed advertising bug in Broadcom controllers Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 121/350] Bluetooth: hci_core: fix init for HCI_USER_CHANNEL Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 123/350] bpf/stackmap: Fix deadlock with rq_lock in bpf_get_stack() Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 132/350] selftests/bpf: Make a copy of subtest name Sasha Levin
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 134/350] net: hns3: log and clear hardware error after reset complete Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 139/350] rtl8xxxu: fix RTL8723BU connection failure issue after warm reboot Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 161/350] i40e: initialize ITRN registers with correct values Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 163/350] i40e: Wrong 'Advertised FEC modes' after set FEC to AUTO Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 164/350] net: phy: dp83867: enable robust auto-mdix Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 178/350] net: dsa: LAN9303: select REGMAP when LAN9303 enable Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 185/350] net: hns3: add struct netdev_queue debug info for TX timeout Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 189/350] net/mlx5e: Verify that rule has at least one fwd/drop action Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 193/350] libbpf: Fix error handling in bpf_map__reuse_fd() Sasha Levin
2019-12-10 21:04 ` [PATCH AUTOSEL 5.4 194/350] Bluetooth: Fix advertising duplicated flags Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 200/350] ixgbe: protect TX timestamping from API misuse Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 211/350] rfkill: allocate static minor Sasha Levin
2019-12-11 7:51 ` Greg Kroah-Hartman
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 212/350] bnx2x: Fix PF-VF communication over multi-cos queues Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 217/350] rtlwifi: fix memory leak in rtl92c_set_fw_rsvdpagepkt() Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 229/350] perf tools: Splice events onto evlist even on error Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 233/350] ice: Check for null pointer dereference when setting rings Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 235/350] perf parse: If pmu configuration fails free terms Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 237/350] net: avoid potential false sharing in neighbor related code Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 242/350] libbpf: Fix negative FD close() in xsk_setup_xdp_prog() Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 243/350] s390/bpf: Use kvcalloc for addrs array Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 248/350] ath10k: fix get invalid tx rate for Mesh metric Sasha Levin
2019-12-10 21:05 ` [PATCH AUTOSEL 5.4 250/350] selftests: net: Fix printf format warnings on arm Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 255/350] ice: delay less Sasha Levin
2019-12-10 21:06 ` Sasha Levin [this message]
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 270/350] net: dsa: sja1105: Disallow management xmit during switch reset Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 271/350] r8169: respect EEE user setting when restarting network Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 274/350] net: ethernet: ti: Add dependency for TI_DAVINCI_EMAC Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 276/350] net: bcmgenet: Add RGMII_RXID support Sasha Levin
2019-12-10 21:49 ` Florian Fainelli
2019-12-19 22:26 ` Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 281/350] qtnfmac: fix debugfs support for multiple cards Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 282/350] qtnfmac: fix invalid channel information output Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 284/350] qtnfmac: fix using skb after free Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 291/350] iwlwifi: mvm: fix unaligned read of rx_pkt_status Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 295/350] tun: fix data-race in gro_normal_list() Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 306/350] selftests, bpf: Fix test_tc_tunnel hanging Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 307/350] selftests, bpf: Workaround an alu32 sub-register spilling issue Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 308/350] bnxt_en: Return proper error code for non-existent NVM variable Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 309/350] net: phy: avoid matching all-ones clause 45 PHY IDs Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 313/350] net-af_xdp: Use correct number of channels from ethtool Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 314/350] brcmfmac: remove monitor interface when detaching Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 319/350] bnxt_en: Improve RX buffer error handling Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 320/350] iwlwifi: check kasprintf() return value Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 323/350] net: ethernet: ti: ale: clean ale tbl on init and intf restart Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 324/350] mt76: fix possible out-of-bound access in mt7615_fill_txs/mt7603_fill_txs Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 326/350] bpf: Switch bpf_map ref counter to atomic64_t so bpf_map_inc() never fails Sasha Levin
2019-12-10 21:28 ` [oss-drivers] " Jakub Kicinski
2019-12-12 16:25 ` Daniel Borkmann
2019-12-19 23:25 ` Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 327/350] libbpf: Fix call relocation offset calculation bug Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 332/350] mac80211: consider QoS Null frames for STA_NULLFUNC_ACKED Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 338/350] ice: Only disable VF state when freeing each VF resources Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 339/350] ice: Fix setting coalesce to handle DCB configuration Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 342/350] net: phy: initialise phydev speed and duplex sanely Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 343/350] tools, bpf: Fix build for 'make -s tools/bpf O=<dir>' Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 346/350] bpf: Provide better register bounds after jmp32 instructions Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 348/350] ibmvnic: Fix completion structure initialization Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 349/350] net: wireless: intel: iwlwifi: fix GRO_NORMAL packet stalling Sasha Levin
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