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authorLorenz Bauer <lmb@cloudflare.com>2021-10-14 15:25:53 +0100
committerMichael Bestas <mkbestas@lineageos.org>2022-04-19 00:51:51 +0300
commitf10e982d3b2ead1b049225b5bd8b149a43e3705b (patch)
treef2b0c94b3ec8991a4e7586457defbc5c747aee4e /kernel/bpf/core.c
parentbfe07625deded524e7b7c68fdbe26dc0b8ada071 (diff)
bpf: Prevent increasing bpf_jit_limit above max
[ Upstream commit fadb7ff1a6c2c565af56b4aacdd086b067eed440 ] Restrict bpf_jit_limit to the maximum supported by the arch's JIT. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211014142554.53120-4-lmb@cloudflare.com Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/bpf/core.c')
-rw-r--r--kernel/bpf/core.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 8def8ae931d9..5c6f4cb9a6c2 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -212,6 +212,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);
int bpf_jit_harden __read_mostly;
long bpf_jit_limit __read_mostly;
+long bpf_jit_limit_max __read_mostly;
static atomic_long_t bpf_jit_current;
@@ -231,7 +232,8 @@ u64 __weak bpf_jit_alloc_exec_limit(void)
static int __init bpf_jit_charge_init(void)
{
/* Only used as heuristic here to derive limit. */
- bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2,
+ bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
+ bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2,
PAGE_SIZE), LONG_MAX);
return 0;
}