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| author | Jan Kratochvil <jan.kratochvil@redhat.com> | 2014-05-19 20:20:27 +0200 |
|---|---|---|
| committer | Jan Kratochvil <jan.kratochvil@redhat.com> | 2014-05-19 20:20:27 +0200 |
| commit | 9e0aa64f5510861b2517c5841b59adde8e423540 (patch) | |
| tree | ae4e687edfd4d85ad434e4809fed15efe3b48469 /gdb | |
| parent | cd8ae15e25c46d8a96ff8b0f6878db0429f460b5 (diff) | |
| download | fsf-binutils-gdb-9e0aa64f5510861b2517c5841b59adde8e423540.zip fsf-binutils-gdb-9e0aa64f5510861b2517c5841b59adde8e423540.tar.gz fsf-binutils-gdb-9e0aa64f5510861b2517c5841b59adde8e423540.tar.bz2 | |
Fix gdbserver qGetTLSAddr for x86_64 -m32
gdbserver makes libthread_db to access uninitialized memory. Surprisingly it
does not harm normally, even -fsanitize=address works with current gdbserver.
I have found just valgrind detects it as a very first warning for gdbserver:
Syscall param ptrace(addr) contains uninitialised byte(s)
at 0x3721EECEBE: ptrace (ptrace.c:45)
by 0x436EE5: ps_get_thread_area (linux-x86-low.c:252)
by 0x5559D02: __td_ta_lookup_th_unique (td_ta_map_lwp2thr.c:157)
by 0x5559EC3: td_ta_map_lwp2thr (td_ta_map_lwp2thr.c:207)
by 0x43F87D: find_one_thread (thread-db.c:281)
by 0x440038: thread_db_get_tls_address (thread-db.c:505)
by 0x40F6D0: handle_query (server.c:2004)
by 0x4124CF: process_serial_event (server.c:3445)
by 0x4136B6: handle_serial_event (server.c:3889)
by 0x419571: handle_file_event (event-loop.c:434)
by 0x418D38: process_event (event-loop.c:189)
by 0x419AB7: start_event_loop (event-loop.c:552)
Reproducible with:
cd gdb/testsuite
g++ -o gdb.threads/tls gdb.threads/tls{,2}.c -m32 -pthread
../gdbserver/gdbserver :1234 gdb.threads/tls
../gdb -batch gdb.threads/tls -ex 'target remote :1234' -ex 'b spin' -ex c -ex 'p a_thread_local'
It is more easily reproducible even without valgrind using s/0x00/0xff/ in the
attached patch. It will then turn the output of reproducer above:
$1 = 0
->
Cannot find thread-local storage for Thread 29044, executable file .../gdb/testsuite/gdb.threads/tls:
Remote target failed to process qGetTLSAddr request
gdb/gdbserver/
2014-05-19 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix gdbserver qGetTLSAddr for x86_64 -m32.
* linux-x86-low.c (X86_64_USER_REGS): New.
(x86_fill_gregset): Call memset for BUF first in x86_64 -m32 case.
Message-ID: <20140410114901.GA16411@host2.jankratochvil.net>
Diffstat (limited to 'gdb')
| -rw-r--r-- | gdb/gdbserver/ChangeLog | 6 | ||||
| -rw-r--r-- | gdb/gdbserver/linux-x86-low.c | 5 |
2 files changed, 11 insertions, 0 deletions
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 4537792..e509c2c 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,9 @@ +2014-05-19 Jan Kratochvil <jan.kratochvil@redhat.com> + + Fix gdbserver qGetTLSAddr for x86_64 -m32. + * linux-x86-low.c (X86_64_USER_REGS): New. + (x86_fill_gregset): Call memset for BUF first in x86_64 -m32 case. + 2014-04-28 Yao Qi <yao@codesourcery.com> * Makefile.in (i386-avx512.c): Fix the typo of generated file diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c index 1bd7b4a..10cd0d5 100644 --- a/gdb/gdbserver/linux-x86-low.c +++ b/gdb/gdbserver/linux-x86-low.c @@ -206,6 +206,7 @@ static const int x86_64_regmap[] = }; #define X86_64_NUM_REGS (sizeof (x86_64_regmap) / sizeof (x86_64_regmap[0])) +#define X86_64_USER_REGS (GS + 1) #else /* ! __x86_64__ */ @@ -364,6 +365,10 @@ x86_fill_gregset (struct regcache *regcache, void *buf) collect_register (regcache, i, ((char *) buf) + x86_64_regmap[i]); return; } + + /* 32-bit inferior registers need to be zero-extended. + Callers would read uninitialized memory otherwise. */ + memset (buf, 0x00, X86_64_USER_REGS * 8); #endif for (i = 0; i < I386_NUM_REGS; i++) |