From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Jan Kratochvil Date: Fri, 27 Oct 2017 21:07:50 +0200 Subject: gdb-6.5-bz216711-clone-is-outermost.patch ;; Fix bogus 0x0 unwind of the thread's topmost function clone(3) (BZ 216711). ;;=fedora https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216711 FIXME: This workaround should be dropped and glibc/sysdeps/unix/sysv/linux/x86_64/clone.S should get CFI for the child instead. 2006-12-17 Jan Kratochvil * gdb/amd64-linux-tdep.c (linux_clone_code): New variable. (LINUX_CLONE_LEN): New definition. (amd64_linux_clone_running, amd64_linux_outermost_frame): New function. (amd64_linux_init_abi): Initialize `outermost_frame_p'. * gdb/i386-tdep.c (i386_gdbarch_init): Likewise. * gdb/i386-tdep.h (gdbarch_tdep): Add `outermost_frame_p' member. * gdb/amd64-tdep.c (amd64_frame_this_id): Call `outermost_frame_p'. 2006-12-17 Jan Kratochvil * gdb.threads/bt-clone-stop.exp, gdb.threads/bt-clone-stop.c: New file. 2007-10-16 Jan Kratochvil Port to GDB-6.7. diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c --- a/gdb/amd64-linux-tdep.c +++ b/gdb/amd64-linux-tdep.c @@ -291,6 +291,80 @@ amd64_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum, /* Set the program counter for process PTID to PC. */ +/* Detect the outermost frame; during unwind of + #5 0x000000305cec68c3 in clone () from /lib64/tls/libc.so.6 + avoid the additional bogus frame + #6 0x0000000000000000 in ?? + We compare if the `linux_clone_code' block is _before_ unwound PC. */ + +static const unsigned char linux_clone_code[] = +{ +/* libc/sysdeps/unix/sysv/linux/x86_64/clone.S */ +/* #ifdef RESET_PID */ +/* ... */ +/* mov $SYS_ify(getpid), %eax */ +/* 0xb8, 0x27, 0x00, 0x00, 0x00 */ +/* OR */ +/* mov $SYS_ify(getpid), %rax */ +/* 0x48, 0xc7, 0xc0, 0x27, 0x00, 0x00, 0x00 */ +/* so just: */ + 0x27, 0x00, 0x00, 0x00, +/* syscall */ + 0x0f, 0x05, +/* movl %eax, %fs:PID */ + 0x64, 0x89, 0x04, 0x25, 0x94, 0x00, 0x00, 0x00, +/* movl %eax, %fs:TID */ + 0x64, 0x89, 0x04, 0x25, 0x90, 0x00, 0x00, 0x00, +/* #endif */ +/* |* Set up arguments for the function call. *| */ +/* popq %rax |* Function to call. *| */ + 0x58, +/* popq %rdi |* Argument. *| */ + 0x5f, +/* call *%rax$ */ + 0xff, 0xd0 +}; + +#define LINUX_CLONE_LEN (sizeof linux_clone_code) + +static int +amd64_linux_clone_running (struct frame_info *this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + unsigned char buf[LINUX_CLONE_LEN]; + + if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_LEN, buf, + LINUX_CLONE_LEN)) + return 0; + + if (memcmp (buf, linux_clone_code, LINUX_CLONE_LEN) != 0) + return 0; + + return 1; +} + +static int +amd64_linux_outermost_frame (struct frame_info *this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + const char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + + /* If we have NAME, we can optimize the search. + `clone' NAME still needs to have the code checked as its name may be + present in the user code. + `__clone' NAME should not be present in the user code but in the initial + parts of the `__clone' implementation the unwind still makes sense. + More detailed unwinding decision would be too much sensitive to possible + subtle changes in specific glibc revisions. */ + if (name == NULL || strcmp (name, "clone") == 0 + || strcmp ("__clone", name) == 0) + return (amd64_linux_clone_running (this_frame) != 0); + + return 0; +} + static void amd64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc) { @@ -1808,6 +1882,8 @@ amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch) tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET; + tdep->outermost_frame_p = amd64_linux_outermost_frame; + /* Add the %orig_rax register used for syscall restarting. */ set_gdbarch_write_pc (gdbarch, amd64_linux_write_pc); diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c --- a/gdb/amd64-tdep.c +++ b/gdb/amd64-tdep.c @@ -2595,6 +2595,7 @@ amd64_frame_unwind_stop_reason (struct frame_info *this_frame, { struct amd64_frame_cache *cache = amd64_frame_cache (this_frame, this_cache); + struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame)); if (!cache->base_p) return UNWIND_UNAVAILABLE; @@ -2603,6 +2604,10 @@ amd64_frame_unwind_stop_reason (struct frame_info *this_frame, if (cache->base == 0) return UNWIND_OUTERMOST; + /* Detect OS dependent outermost frames; such as `clone'. */ + if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame)) + return UNWIND_OUTERMOST; + return UNWIND_NO_REASON; } @@ -2737,6 +2742,7 @@ amd64_sigtramp_frame_this_id (struct frame_info *this_frame, { struct amd64_frame_cache *cache = amd64_sigtramp_frame_cache (this_frame, this_cache); + struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame)); if (!cache->base_p) (*this_id) = frame_id_build_unavailable_stack (get_frame_pc (this_frame)); @@ -2745,6 +2751,11 @@ amd64_sigtramp_frame_this_id (struct frame_info *this_frame, /* This marks the outermost frame. */ return; } + else if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame)) + { + /* Detect OS dependent outermost frames; such as `clone'. */ + return; + } else (*this_id) = frame_id_build (cache->base + 16, get_frame_pc (this_frame)); } diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -8406,6 +8406,9 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) tdep->xsave_xcr0_offset = -1; + /* Unwinding stops on i386 automatically. */ + tdep->outermost_frame_p = NULL; + tdep->record_regmap = i386_record_regmap; set_gdbarch_type_align (gdbarch, i386_type_align); diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h --- a/gdb/i386-tdep.h +++ b/gdb/i386-tdep.h @@ -251,6 +251,9 @@ struct gdbarch_tdep /* Regsets. */ const struct regset *fpregset; + + /* Detect OS dependent outermost frames; such as `clone'. */ + int (*outermost_frame_p) (struct frame_info *this_frame); }; /* Floating-point registers. */ diff --git a/gdb/testsuite/gdb.threads/bt-clone-stop.c b/gdb/testsuite/gdb.threads/bt-clone-stop.c new file mode 100644 --- /dev/null +++ b/gdb/testsuite/gdb.threads/bt-clone-stop.c @@ -0,0 +1,39 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2006 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301, USA. */ + + +#include +#include +#include + + +void *threader (void *arg) +{ + assert (0); + return NULL; +} + +int main (void) +{ + pthread_t t1; + + pthread_create (&t1, NULL, threader, (void *) NULL); + for (;;) + pause(); +} diff --git a/gdb/testsuite/gdb.threads/bt-clone-stop.exp b/gdb/testsuite/gdb.threads/bt-clone-stop.exp new file mode 100644 --- /dev/null +++ b/gdb/testsuite/gdb.threads/bt-clone-stop.exp @@ -0,0 +1,61 @@ +# Copyright 2006 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + +# Backtraced `clone' must not have `PC == 0' as its previous frame. + +if $tracelevel then { + strace $tracelevel +} + +set testfile bt-clone-stop +set srcfile ${testfile}.c +set binfile [standard_output_file ${testfile}] +if { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { + untested "Couldn't compile test program" + return -1 +} + +# Get things started. + +gdb_exit +gdb_start +gdb_reinitialize_dir $srcdir/$subdir +gdb_load ${binfile} + +# threader: threader.c:8: threader: Assertion `0' failed. +# Program received signal SIGABRT, Aborted. + +gdb_test "run" \ + {Thread 2 "bt-clone-stop" received signal SIGABRT.*} \ + "run" + +# Former gdb unwind (the first function is `clone'): +# #5 0x0000003421ecd62d in ?? () from /lib64/libc.so.6 +# #6 0x0000000000000000 in ?? () +# (gdb) +# Tested `amd64_linux_outermost_frame' functionality should omit the line `#6'. +# +# Two `-re' cases below must be in this order (1st is a subset of the 2nd one). +# Unhandled case below should not happen and it is fortunately handled by +# `amd64_linux_outermost_frame' as FAIL (and result `0x0 entry output invalid'). +gdb_test_multiple "bt" "0x0 entry output invalid" { + -re "in threader \\(.*\n#\[0-9\]* *0x0* in .*$gdb_prompt $" { + fail "0x0 entry found" + } + -re "in threader \\(.*$gdb_prompt $" { + pass "0x0 entry not found" + } +}