From: Andrii Nakryiko andrii@kernel.org
stable inclusion from stable-5.10.80 commit 5be42b203f2c4b72205b4ecd72c0558dfdb3a552 bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit a20eac0af02810669e187cb623bc904908c423af upstream.
Previous fix aded bpf_clamp_umax() helper use to re-validate boundaries. While that works correctly, it introduces more branches, which blows up past 1 million instructions in no-alu32 variant of strobemeta selftests.
Switching len variable from u32 to u64 also fixes the issue and reduces the number of validated instructions, so use that instead. Fix this patch and bpf_clamp_umax() removed, both alu32 and no-alu32 selftests pass.
Fixes: 0133c20480b1 ("selftests/bpf: Fix strobemeta selftest regression") Signed-off-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Link: https://lore.kernel.org/bpf/20211101230118.1273019-1-andrii@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Weilong Chen chenweilong@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- tools/testing/selftests/bpf/progs/strobemeta.h | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/strobemeta.h b/tools/testing/selftests/bpf/progs/strobemeta.h index 3687ea755ab5..60c93aee2f4a 100644 --- a/tools/testing/selftests/bpf/progs/strobemeta.h +++ b/tools/testing/selftests/bpf/progs/strobemeta.h @@ -10,14 +10,6 @@ #include <linux/types.h> #include <bpf/bpf_helpers.h>
-#define bpf_clamp_umax(VAR, UMAX) \ - asm volatile ( \ - "if %0 <= %[max] goto +1\n" \ - "%0 = %[max]\n" \ - : "+r"(VAR) \ - : [max]"i"(UMAX) \ - ) - typedef uint32_t pid_t; struct task_struct {};
@@ -366,7 +358,7 @@ static __always_inline uint64_t read_str_var(struct strobemeta_cfg *cfg, void *payload) { void *location; - uint32_t len; + uint64_t len;
data->str_lens[idx] = 0; location = calc_location(&cfg->str_locs[idx], tls_base); @@ -398,7 +390,7 @@ static __always_inline void *read_map_var(struct strobemeta_cfg *cfg, struct strobe_map_descr* descr = &data->map_descrs[idx]; struct strobe_map_raw map; void *location; - uint32_t len; + uint64_t len; int i;
descr->tag_len = 0; /* presume no tag is set */ @@ -421,7 +413,6 @@ static __always_inline void *read_map_var(struct strobemeta_cfg *cfg,
len = bpf_probe_read_user_str(payload, STROBE_MAX_STR_LEN, map.tag); if (len <= STROBE_MAX_STR_LEN) { - bpf_clamp_umax(len, STROBE_MAX_STR_LEN); descr->tag_len = len; payload += len; } @@ -439,7 +430,6 @@ static __always_inline void *read_map_var(struct strobemeta_cfg *cfg, len = bpf_probe_read_user_str(payload, STROBE_MAX_STR_LEN, map.entries[i].key); if (len <= STROBE_MAX_STR_LEN) { - bpf_clamp_umax(len, STROBE_MAX_STR_LEN); descr->key_lens[i] = len; payload += len; } @@ -447,7 +437,6 @@ static __always_inline void *read_map_var(struct strobemeta_cfg *cfg, len = bpf_probe_read_user_str(payload, STROBE_MAX_STR_LEN, map.entries[i].val); if (len <= STROBE_MAX_STR_LEN) { - bpf_clamp_umax(len, STROBE_MAX_STR_LEN); descr->val_lens[i] = len; payload += len; }