On Mon, Dec 11, 2023 at 07:29:40PM +0800, Hou Tao wrote: SNIP > > It seems a big attr->link_create.uprobe_multi.cnt is passed to > bpf_uprobe_multi_link_attach(). Could you please try the first patch in > the following patch set ? > > https://lore.kernel.org/bpf/20231211112843.4147157-1-houtao@xxxxxxxxxxxxxxx/T/#t > > [ 68.389633][ T8223] ? __might_fault+0x13f/0x1a0 > > [ 68.390129][ T8223] ? bpf_kprobe_multi_link_attach+0x10/0x10 > > SNIP > > res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x20000140ul, /*size=*/0x90ul); > > if (res != -1) r[0] = res; > > memcpy((void*)0x20000000, "./file0\000", 8); > > syscall(__NR_creat, /*file=*/0x20000000ul, /*mode=*/0ul); > > *(uint32_t*)0x20000340 = r[0]; > > *(uint32_t*)0x20000344 = 0; > > *(uint32_t*)0x20000348 = 0x30; > > *(uint32_t*)0x2000034c = 0; > > *(uint64_t*)0x20000350 = 0x20000080; > > memcpy((void*)0x20000080, "./file0\000", 8); > > 0x20000350 is the address of attr->link_create.uprobe_multi.path. > > *(uint64_t*)0x20000358 = 0x200000c0; > > *(uint64_t*)0x200000c0 = 0; > > *(uint64_t*)0x20000360 = 0; > > *(uint64_t*)0x20000368 = 0; > > *(uint32_t*)0x20000370 = 0xffffff1f; > > The value of attr->link_create.uprobe_multi.cnt is 0xffffff1f, so > 0xffffff1f * sizeof(bpf_uprobe) will be greater than INT_MAX, and > triggers the warning in mm/util.c: > > /* Don't even allow crazy sizes */ > if (unlikely(size > INT_MAX)) { > WARN_ON_ONCE(!(flags & __GFP_NOWARN)); > return NULL; > } > > Adding __GFP_NOWARN when doing kvcalloc() can fix the warning. hi, looks like that's the case.. thanks for fixing that btw while checking on that I found kprobe_multi bench attach test takes forever on latest bpf-next/master test_kprobe_multi_bench_attach:PASS:bpf_program__attach_kprobe_multi_opts 0 nsec test_kprobe_multi_bench_attach: found 56140 functions test_kprobe_multi_bench_attach: attached in 89.174s test_kprobe_multi_bench_attach: detached in 13.245s #113/1 kprobe_multi_bench_attach/kernel:OK Masami, any idea of any change on fprobe/ftrace side recently? I'm going to check ;-) thanks, jirka
