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authorLorenz Bauer <lmb@cloudflare.com>2021-10-14 15:25:53 +0100
committerAlexei Starovoitov <ast@kernel.org>2021-10-22 17:23:53 -0700
commitfadb7ff1a6c2c565af56b4aacdd086b067eed440 (patch)
tree3e5cda8336b05541dd33b7888ba131c1bc910871 /kernel/bpf/core.c
parent5d63ae908242f028bd10860cba98450d11c079b8 (diff)
downloadlinux-fadb7ff1a6c2c565af56b4aacdd086b067eed440.tar.bz2
bpf: Prevent increasing bpf_jit_limit above max
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
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 d6b7dfdd8066..c1e7eb3f1876 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -524,6 +524,7 @@ int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_harden __read_mostly;
long bpf_jit_limit __read_mostly;
+long bpf_jit_limit_max __read_mostly;
static void
bpf_prog_ksym_set_addr(struct bpf_prog *prog)
@@ -817,7 +818,8 @@ 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;
}