From: Yonghong Song yhs@fb.com
[ Upstream commit de920fc64cbaa031f947e9be964bda05fd090380 ]
x86 bpf_jit_comp.c used kmalloc_array to store jited addresses for each bpf insn. With a large bpf program, we have see the following allocation failures in our production server:
page allocation failure: order:5, mode:0x40cc0(GFP_KERNEL|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0" Call Trace: dump_stack+0x50/0x70 warn_alloc.cold.120+0x72/0xd2 ? __alloc_pages_direct_compact+0x157/0x160 __alloc_pages_slowpath+0xcdb/0xd00 ? get_page_from_freelist+0xe44/0x1600 ? vunmap_page_range+0x1ba/0x340 __alloc_pages_nodemask+0x2c9/0x320 kmalloc_order+0x18/0x80 kmalloc_order_trace+0x1d/0xa0 bpf_int_jit_compile+0x1e2/0x484 ? kmalloc_order_trace+0x1d/0xa0 bpf_prog_select_runtime+0xc3/0x150 bpf_prog_load+0x480/0x720 ? __mod_memcg_lruvec_state+0x21/0x100 __do_sys_bpf+0xc31/0x2040 ? close_pdeo+0x86/0xe0 do_syscall_64+0x42/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f2f300f7fa9 Code: Bad RIP value.
Dumped assembly:
ffffffff810b6d70 <bpf_int_jit_compile>: ; { ffffffff810b6d70: e8 eb a5 b4 00 callq 0xffffffff81c01360 <__fentry__> ffffffff810b6d75: 41 57 pushq %r15 ... ffffffff810b6f39: e9 72 fe ff ff jmp 0xffffffff810b6db0 <bpf_int_jit_compile+0x40> ; addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL); ffffffff810b6f3e: 8b 45 0c movl 12(%rbp), %eax ; return __kmalloc(bytes, flags); ffffffff810b6f41: be c0 0c 00 00 movl $3264, %esi ; addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL); ffffffff810b6f46: 8d 78 01 leal 1(%rax), %edi ; if (unlikely(check_mul_overflow(n, size, &bytes))) ffffffff810b6f49: 48 c1 e7 02 shlq $2, %rdi ; return __kmalloc(bytes, flags); ffffffff810b6f4d: e8 8e 0c 1d 00 callq 0xffffffff81287be0 <__kmalloc> ; if (!addrs) { ffffffff810b6f52: 48 85 c0 testq %rax, %rax
Change kmalloc_array() to kvmalloc_array() to avoid potential allocation error for big bpf programs.
Signed-off-by: Yonghong Song yhs@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20210309015647.3657852-1-yhs@fb.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/net/bpf_jit_comp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 023ac12f54a2..4cf3612ccd37 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2038,7 +2038,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) extra_pass = true; goto skip_init_addrs; } - addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL); + addrs = kvmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL); if (!addrs) { prog = orig_prog; goto out_addrs; @@ -2128,7 +2128,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (image) bpf_prog_fill_jited_linfo(prog, addrs + 1); out_addrs: - kfree(addrs); + kvfree(addrs); kfree(jit_data); prog->aux->jit_data = NULL; }