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authorAlexei Starovoitov <ast@kernel.org>2026-06-13 11:07:55 -0700
committerAlexei Starovoitov <ast@kernel.org>2026-06-14 13:47:38 -0700
commit2148794eeaf2a898adc791e9472eb80ea55984da (patch)
tree5cd3a18452e6bca3122faf213779fbc5ea619a52 /kernel
parent7bfb93e3475be9de894f1cecd3a727d3e1649b03 (diff)
bpf: Raise maximum call chain depth to 16 frames
Bump MAX_CALL_FRAMES from 8 to 16 to allow deeper call chains that Rust-BPF requires and update selftests. Link: https://lore.kernel.org/r/20260613180755.29671-1-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/verifier.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index eb46a81a8c51..2abc79dbf281 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3144,7 +3144,7 @@ static void mark_indirect_target(struct bpf_verifier_env *env, int idx)
env->insn_aux_data[idx].indirect_target = true;
}
-#define LR_FRAMENO_BITS 3
+#define LR_FRAMENO_BITS 4
#define LR_SPI_BITS 6
#define LR_ENTRY_BITS (LR_SPI_BITS + LR_FRAMENO_BITS + 1)
#define LR_SIZE_BITS 4
@@ -3153,7 +3153,11 @@ static void mark_indirect_target(struct bpf_verifier_env *env, int idx)
#define LR_SIZE_MASK ((1ull << LR_SIZE_BITS) - 1)
#define LR_SPI_OFF LR_FRAMENO_BITS
#define LR_IS_REG_OFF (LR_SPI_BITS + LR_FRAMENO_BITS)
-#define LINKED_REGS_MAX 6
+#define LINKED_REGS_MAX 5
+
+static_assert(MAX_CALL_FRAMES <= (1 << LR_FRAMENO_BITS));
+static_assert(LINKED_REGS_MAX < (1 << LR_SIZE_BITS));
+static_assert(LINKED_REGS_MAX * LR_ENTRY_BITS + LR_SIZE_BITS <= 64);
struct linked_reg {
u8 frameno;
@@ -3177,10 +3181,11 @@ static struct linked_reg *linked_regs_push(struct linked_regs *s)
return NULL;
}
-/* Use u64 as a vector of 6 10-bit values, use first 4-bits to track
+/*
+ * Use u64 as a vector of 5 11-bit values, use first 4-bits to track
* number of elements currently in stack.
- * Pack one history entry for linked registers as 10 bits in the following format:
- * - 3-bits frameno
+ * Pack one history entry for linked registers as 11 bits in the following format:
+ * - 4-bits frameno
* - 6-bits spi_or_reg
* - 1-bit is_reg
*/