From: Fuad Tabba <tabba@google.com> mainline inclusion from mainline-v7.0-rc2 commit ef06fd16d48704eac868441d98d4ef083d8f3d07 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8762 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- struct bpf_plt contains a u64 target field. Currently, the BPF JIT allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT buffer. Because the base address of the JIT buffer can be 4-byte aligned (e.g., ending in 0x4 or 0xc), the relative padding logic in build_plt() fails to ensure that target lands on an 8-byte boundary. This leads to two issues: 1. UBSAN reports misaligned-access warnings when dereferencing the structure. 2. More critically, target is updated concurrently via WRITE_ONCE() in bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64, 64-bit loads/stores are only guaranteed to be single-copy atomic if they are 64-bit aligned. A misaligned target risks a torn read, causing the JIT to jump to a corrupted address. Fix this by increasing the allocation alignment requirement to 8 bytes (sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of the JIT buffer to an 8-byte boundary, allowing the relative padding math in build_plt() to correctly align the target field. Fixes: b2ad54e1533e ("bpf, arm64: Implement bpf_arch_text_poke() for arm64") Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20260226075525.233321-1-tabba@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Conflicts: arch/arm64/net/bpf_jit_comp.c [The conflicts were due to not merge commit 1dad391daef1] Signed-off-by: Pu Lehui <pulehui@huawei.com> --- arch/arm64/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index f98ae8bf4e19..2494a5c96489 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1648,7 +1648,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) extable_offset = round_up(prog_size + PLT_TARGET_SIZE, extable_align); image_size = extable_offset + extable_size; header = bpf_jit_binary_alloc(image_size, &image_ptr, - sizeof(u32), jit_fill_hole); + sizeof(u64), jit_fill_hole); if (header == NULL) { prog = orig_prog; goto out_off; -- 2.34.1