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author | Ingo Molnar <mingo@kernel.org> | 2016-05-05 08:35:00 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2016-05-05 08:35:00 +0200 |
commit | 1fb48f8e54e5ed4d3d8599ba7e83f1f60530c81c (patch) | |
tree | 6b8c1ccdd461e211f72c674d183f5129f5fe4a5b /tools | |
parent | 778843f934e362ed4ed734520f60a44a78a074b4 (diff) | |
parent | 04974df8049fc4240d22759a91e035082ccd18b4 (diff) | |
download | linux-1fb48f8e54e5ed4d3d8599ba7e83f1f60530c81c.tar.gz linux-1fb48f8e54e5ed4d3d8599ba7e83f1f60530c81c.tar.bz2 linux-1fb48f8e54e5ed4d3d8599ba7e83f1f60530c81c.zip |
Merge tag 'v4.6-rc6' into x86/asm, to refresh the tree
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/objtool/Documentation/stack-validation.txt | 38 | ||||
-rw-r--r-- | tools/objtool/builtin-check.c | 97 | ||||
-rw-r--r-- | tools/perf/util/intel-pt.c | 2 | ||||
-rw-r--r-- | tools/testing/selftests/net/.gitignore | 1 | ||||
-rw-r--r-- | tools/testing/selftests/net/Makefile | 2 | ||||
-rw-r--r-- | tools/testing/selftests/net/reuseport_dualstack.c | 208 |
6 files changed, 312 insertions, 36 deletions
diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt index 5a95896105bc..55a60d331f47 100644 --- a/tools/objtool/Documentation/stack-validation.txt +++ b/tools/objtool/Documentation/stack-validation.txt @@ -299,18 +299,38 @@ they mean, and suggestions for how to fix them. Errors in .c files ------------------ -If you're getting an objtool error in a compiled .c file, chances are -the file uses an asm() statement which has a "call" instruction. An -asm() statement with a call instruction must declare the use of the -stack pointer in its output operand. For example, on x86_64: +1. c_file.o: warning: objtool: funcA() falls through to next function funcB() - register void *__sp asm("rsp"); - asm volatile("call func" : "+r" (__sp)); + This means that funcA() doesn't end with a return instruction or an + unconditional jump, and that objtool has determined that the function + can fall through into the next function. There could be different + reasons for this: -Otherwise the stack frame may not get created before the call. + 1) funcA()'s last instruction is a call to a "noreturn" function like + panic(). In this case the noreturn function needs to be added to + objtool's hard-coded global_noreturns array. Feel free to bug the + objtool maintainer, or you can submit a patch. -Another possible cause for errors in C code is if the Makefile removes --fno-omit-frame-pointer or adds -fomit-frame-pointer to the gcc options. + 2) funcA() uses the unreachable() annotation in a section of code + that is actually reachable. + + 3) If funcA() calls an inline function, the object code for funcA() + might be corrupt due to a gcc bug. For more details, see: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70646 + +2. If you're getting any other objtool error in a compiled .c file, it + may be because the file uses an asm() statement which has a "call" + instruction. An asm() statement with a call instruction must declare + the use of the stack pointer in its output operand. For example, on + x86_64: + + register void *__sp asm("rsp"); + asm volatile("call func" : "+r" (__sp)); + + Otherwise the stack frame may not get created before the call. + +3. Another possible cause for errors in C code is if the Makefile removes + -fno-omit-frame-pointer or adds -fomit-frame-pointer to the gcc options. Also see the above section for .S file errors for more information what the individual error messages mean. diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 7515cb2e879a..e8a1e69eb92c 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -54,6 +54,7 @@ struct instruction { struct symbol *call_dest; struct instruction *jump_dest; struct list_head alts; + struct symbol *func; }; struct alternative { @@ -66,6 +67,7 @@ struct objtool_file { struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 16); struct section *rodata, *whitelist; + bool ignore_unreachables, c_file; }; const char *objname; @@ -228,7 +230,7 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func, } } - if (insn->type == INSN_JUMP_DYNAMIC) + if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts)) /* sibling call */ return 0; } @@ -248,6 +250,7 @@ static int dead_end_function(struct objtool_file *file, struct symbol *func) static int decode_instructions(struct objtool_file *file) { struct section *sec; + struct symbol *func; unsigned long offset; struct instruction *insn; int ret; @@ -281,6 +284,21 @@ static int decode_instructions(struct objtool_file *file) hash_add(file->insn_hash, &insn->hash, insn->offset); list_add_tail(&insn->list, &file->insn_list); } + + list_for_each_entry(func, &sec->symbol_list, list) { + if (func->type != STT_FUNC) + continue; + + if (!find_insn(file, sec, func->offset)) { + WARN("%s(): can't find starting instruction", + func->name); + return -1; + } + + func_for_each_insn(file, func, insn) + if (!insn->func) + insn->func = func; + } } return 0; @@ -664,13 +682,40 @@ static int add_func_switch_tables(struct objtool_file *file, text_rela->addend); /* - * TODO: Document where this is needed, or get rid of it. - * * rare case: jmpq *[addr](%rip) + * + * This check is for a rare gcc quirk, currently only seen in + * three driver functions in the kernel, only with certain + * obscure non-distro configs. + * + * As part of an optimization, gcc makes a copy of an existing + * switch jump table, modifies it, and then hard-codes the jump + * (albeit with an indirect jump) to use a single entry in the + * table. The rest of the jump table and some of its jump + * targets remain as dead code. + * + * In such a case we can just crudely ignore all unreachable + * instruction warnings for the entire object file. Ideally we + * would just ignore them for the function, but that would + * require redesigning the code quite a bit. And honestly + * that's just not worth doing: unreachable instruction + * warnings are of questionable value anyway, and this is such + * a rare issue. + * + * kbuild reports: + * - https://lkml.kernel.org/r/201603231906.LWcVUpxm%25fengguang.wu@intel.com + * - https://lkml.kernel.org/r/201603271114.K9i45biy%25fengguang.wu@intel.com + * - https://lkml.kernel.org/r/201603291058.zuJ6ben1%25fengguang.wu@intel.com + * + * gcc bug: + * - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70604 */ - if (!rodata_rela) + if (!rodata_rela) { rodata_rela = find_rela_by_dest(file->rodata, text_rela->addend + 4); + if (rodata_rela) + file->ignore_unreachables = true; + } if (!rodata_rela) continue; @@ -732,9 +777,6 @@ static int decode_sections(struct objtool_file *file) { int ret; - file->whitelist = find_section_by_name(file->elf, "__func_stack_frame_non_standard"); - file->rodata = find_section_by_name(file->elf, ".rodata"); - ret = decode_instructions(file); if (ret) return ret; @@ -799,6 +841,7 @@ static int validate_branch(struct objtool_file *file, struct alternative *alt; struct instruction *insn; struct section *sec; + struct symbol *func = NULL; unsigned char state; int ret; @@ -813,6 +856,16 @@ static int validate_branch(struct objtool_file *file, } while (1) { + if (file->c_file && insn->func) { + if (func && func != insn->func) { + WARN("%s() falls through to next function %s()", + func->name, insn->func->name); + return 1; + } + + func = insn->func; + } + if (insn->visited) { if (frame_state(insn->state) != frame_state(state)) { WARN_FUNC("frame pointer state mismatch", @@ -823,13 +876,6 @@ static int validate_branch(struct objtool_file *file, return 0; } - /* - * Catch a rare case where a noreturn function falls through to - * the next function. - */ - if (is_fentry_call(insn) && (state & STATE_FENTRY)) - return 0; - insn->visited = true; insn->state = state; @@ -1035,12 +1081,8 @@ static int validate_functions(struct objtool_file *file) continue; insn = find_insn(file, sec, func->offset); - if (!insn) { - WARN("%s(): can't find starting instruction", - func->name); - warnings++; + if (!insn) continue; - } ret = validate_branch(file, insn, 0); warnings += ret; @@ -1056,13 +1098,14 @@ static int validate_functions(struct objtool_file *file) if (insn->visited) continue; - if (!ignore_unreachable_insn(func, insn) && - !warnings) { - WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset); - warnings++; - } - insn->visited = true; + + if (file->ignore_unreachables || warnings || + ignore_unreachable_insn(func, insn)) + continue; + + WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset); + warnings++; } } } @@ -1133,6 +1176,10 @@ int cmd_check(int argc, const char **argv) INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); + file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard"); + file.rodata = find_section_by_name(file.elf, ".rodata"); + file.ignore_unreachables = false; + file.c_file = find_section_by_name(file.elf, ".comment"); ret = decode_sections(&file); if (ret < 0) diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index 407f11b97c8d..617578440989 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -1130,7 +1130,7 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq) pr_err("Intel Processor Trace: failed to deliver transaction event, error %d\n", ret); - if (pt->synth_opts.callchain) + if (pt->synth_opts.last_branch) intel_pt_reset_last_branch_rb(ptq); return ret; diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index 69bb3fc38fb2..0840684deb7d 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -3,3 +3,4 @@ psock_fanout psock_tpacket reuseport_bpf reuseport_bpf_cpu +reuseport_dualstack diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index c658792d47b4..0e5340742620 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -4,7 +4,7 @@ CFLAGS = -Wall -O2 -g CFLAGS += -I../../../../usr/include/ -NET_PROGS = socket psock_fanout psock_tpacket reuseport_bpf reuseport_bpf_cpu +NET_PROGS = socket psock_fanout psock_tpacket reuseport_bpf reuseport_bpf_cpu reuseport_dualstack all: $(NET_PROGS) %: %.c diff --git a/tools/testing/selftests/net/reuseport_dualstack.c b/tools/testing/selftests/net/reuseport_dualstack.c new file mode 100644 index 000000000000..90958aaaafb9 --- /dev/null +++ b/tools/testing/selftests/net/reuseport_dualstack.c @@ -0,0 +1,208 @@ +/* + * It is possible to use SO_REUSEPORT to open multiple sockets bound to + * equivalent local addresses using AF_INET and AF_INET6 at the same time. If + * the AF_INET6 socket has IPV6_V6ONLY set, it's clear which socket should + * receive a given incoming packet. However, when it is not set, incoming v4 + * packets should prefer the AF_INET socket(s). This behavior was defined with + * the original SO_REUSEPORT implementation, but broke with + * e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") + * This test creates these mixed AF_INET/AF_INET6 sockets and asserts the + * AF_INET preference for v4 packets. + */ + +#define _GNU_SOURCE + +#include <arpa/inet.h> +#include <errno.h> +#include <error.h> +#include <linux/in.h> +#include <linux/unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/epoll.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <unistd.h> + +static const int PORT = 8888; + +static void build_rcv_fd(int family, int proto, int *rcv_fds, int count) +{ + struct sockaddr_storage addr; + struct sockaddr_in *addr4; + struct sockaddr_in6 *addr6; + int opt, i; + + switch (family) { + case AF_INET: + addr4 = (struct sockaddr_in *)&addr; + addr4->sin_family = AF_INET; + addr4->sin_addr.s_addr = htonl(INADDR_ANY); + addr4->sin_port = htons(PORT); + break; + case AF_INET6: + addr6 = (struct sockaddr_in6 *)&addr; + addr6->sin6_family = AF_INET6; + addr6->sin6_addr = in6addr_any; + addr6->sin6_port = htons(PORT); + break; + default: + error(1, 0, "Unsupported family %d", family); + } + + for (i = 0; i < count; ++i) { + rcv_fds[i] = socket(family, proto, 0); + if (rcv_fds[i] < 0) + error(1, errno, "failed to create receive socket"); + + opt = 1; + if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt, + sizeof(opt))) + error(1, errno, "failed to set SO_REUSEPORT"); + + if (bind(rcv_fds[i], (struct sockaddr *)&addr, sizeof(addr))) + error(1, errno, "failed to bind receive socket"); + + if (proto == SOCK_STREAM && listen(rcv_fds[i], 10)) + error(1, errno, "failed to listen on receive port"); + } +} + +static void send_from_v4(int proto) +{ + struct sockaddr_in saddr, daddr; + int fd; + + saddr.sin_family = AF_INET; + saddr.sin_addr.s_addr = htonl(INADDR_ANY); + saddr.sin_port = 0; + + daddr.sin_family = AF_INET; + daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); + daddr.sin_port = htons(PORT); + + fd = socket(AF_INET, proto, 0); + if (fd < 0) + error(1, errno, "failed to create send socket"); + + if (bind(fd, (struct sockaddr *)&saddr, sizeof(saddr))) + error(1, errno, "failed to bind send socket"); + + if (connect(fd, (struct sockaddr *)&daddr, sizeof(daddr))) + error(1, errno, "failed to connect send socket"); + + if (send(fd, "a", 1, 0) < 0) + error(1, errno, "failed to send message"); + + close(fd); +} + +static int receive_once(int epfd, int proto) +{ + struct epoll_event ev; + int i, fd; + char buf[8]; + + i = epoll_wait(epfd, &ev, 1, -1); + if (i < 0) + error(1, errno, "epoll_wait failed"); + + if (proto == SOCK_STREAM) { + fd = accept(ev.data.fd, NULL, NULL); + if (fd < 0) + error(1, errno, "failed to accept"); + i = recv(fd, buf, sizeof(buf), 0); + close(fd); + } else { + i = recv(ev.data.fd, buf, sizeof(buf), 0); + } + + if (i < 0) + error(1, errno, "failed to recv"); + + return ev.data.fd; +} + +static void test(int *rcv_fds, int count, int proto) +{ + struct epoll_event ev; + int epfd, i, test_fd; + uint16_t test_family; + socklen_t len; + + epfd = epoll_create(1); + if (epfd < 0) + error(1, errno, "failed to create epoll"); + + ev.events = EPOLLIN; + for (i = 0; i < count; ++i) { + ev.data.fd = rcv_fds[i]; + if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev)) + error(1, errno, "failed to register sock epoll"); + } + + send_from_v4(proto); + + test_fd = receive_once(epfd, proto); + if (getsockopt(test_fd, SOL_SOCKET, SO_DOMAIN, &test_family, &len)) + error(1, errno, "failed to read socket domain"); + if (test_family != AF_INET) + error(1, 0, "expected to receive on v4 socket but got v6 (%d)", + test_family); + + close(epfd); +} + +int main(void) +{ + int rcv_fds[32], i; + + fprintf(stderr, "---- UDP IPv4 created before IPv6 ----\n"); + build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 5); + build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[5]), 5); + test(rcv_fds, 10, SOCK_DGRAM); + for (i = 0; i < 10; ++i) + close(rcv_fds[i]); + + fprintf(stderr, "---- UDP IPv6 created before IPv4 ----\n"); + build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 5); + build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[5]), 5); + test(rcv_fds, 10, SOCK_DGRAM); + for (i = 0; i < 10; ++i) + close(rcv_fds[i]); + + /* NOTE: UDP socket lookups traverse a different code path when there + * are > 10 sockets in a group. + */ + fprintf(stderr, "---- UDP IPv4 created before IPv6 (large) ----\n"); + build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 16); + build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[16]), 16); + test(rcv_fds, 32, SOCK_DGRAM); + for (i = 0; i < 32; ++i) + close(rcv_fds[i]); + + fprintf(stderr, "---- UDP IPv6 created before IPv4 (large) ----\n"); + build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 16); + build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[16]), 16); + test(rcv_fds, 32, SOCK_DGRAM); + for (i = 0; i < 32; ++i) + close(rcv_fds[i]); + + fprintf(stderr, "---- TCP IPv4 created before IPv6 ----\n"); + build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 5); + build_rcv_fd(AF_INET6, SOCK_STREAM, &(rcv_fds[5]), 5); + test(rcv_fds, 10, SOCK_STREAM); + for (i = 0; i < 10; ++i) + close(rcv_fds[i]); + + fprintf(stderr, "---- TCP IPv6 created before IPv4 ----\n"); + build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds, 5); + build_rcv_fd(AF_INET, SOCK_STREAM, &(rcv_fds[5]), 5); + test(rcv_fds, 10, SOCK_STREAM); + for (i = 0; i < 10; ++i) + close(rcv_fds[i]); + + fprintf(stderr, "SUCCESS\n"); + return 0; +} |