Commit Graph

7 Commits

Author SHA1 Message Date
Richard Weinberger fc9a00187b um: set __HAVE_ARCH_GATE_AREA for x86_64
Implement arch_vma_name() and make get_gate_vma(), in_gate_area() and
in_gate_area_no_mm() a nop.

We need arch_vma_name() to support vDSO.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:13 -07:00
Paul Pluzhnikov 13e165baf6 uml: kernels on {i386,x86_64} produce bad coredumps
One of our users reported that when a user-level program SIGSEGVs under
UML kernel, the resulting core dump is not very usable.

I have reproduced that with the latest kernel:

  make ARCH=um defconfig; make ARCH=um

Run the resulting kernel, then "inside" run this program:

#include <pthread.h>

void *fn(void *p)
{
 abort();
}

int main()
{
 pthread_t tid;
 pthread_create(&tid, 0, fn, 0);
 pthread_join(tid, 0);
 return 0;
}

Analyze the coredump with GDB. Here is what you'll see:

sudo gdb -q -ex 'set solib-absolute-prefix ../root_fs' -ex 'file ../root_fs/var/tmp/mt-abort' -ex 'core ../root_fs/var/tmp/core.762'
Reading symbols from /usr/local/google/root_fs/var/tmp/mt-abort...done.
[New Thread 763]
[New Thread 762]
Core was generated by `./mt-abort'.
Program terminated with signal 6, Aborted.
#0  0x0000000040255250 in raise () from ../root_fs/lib64/libc.so.6
(gdb) info thread
  2 Thread 762  0x0000000000000000 in ?? ()
* 1 Thread 763  0x0000000040255250 in raise () from ../root_fs/lib64/libc.so.6

Note that thread#2 looks funny.

(gdb) thread 2
[Switching to thread 2 (Thread 762)]#0  0x0000000000000000 in ?? ()
(gdb) info reg
rax            0x0      0
rbx            0x0      0
rcx            0x0      0
rdx            0x0      0
rsi            0x0      0
rdi            0x0      0
rbp            0x0      0x0
rsp            0x0      0x0
r8             0x0      0
r9             0x0      0
r10            0x0      0
r11            0x0      0
r12            0x0      0
r13            0x0      0
r14            0x0      0
r15            0x0      0
rip            0x0      0
eflags         0x0      [ ]
cs             0x0      0
ss             0x0      0
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0

Examining the core shows that NT_PRSTATUS notes for all threads other than
the one that crashed are zeroed out.

I believe this is happening because neither ELF_CORE_COPY_TASK_REGS nor
task_pt_regs are defined under ARCH=um, and so elf_core_copy_task_regs()
becomes a no-op.

Attached patch fixes this for SUBARCH={x86_64,i386}.

Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
Cc: Jeff Dike <jdike@addtoit.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:09 -07:00
Jan Kiszka 4cb3ca7cd7 UML: Fix compiler warning due to missing task_struct declaration
We can't pull in linux/sched.h due to circular dependency, so just
forward-declare the struct.

This fixes the following warning:

  CC      arch/um/sys-i386/elfcore.o
In file included from /data/linux-2.6/include/linux/elf.h:8,
                 from /data/linux-2.6/arch/um/sys-i386/elfcore.c:2:
arch/um/sys-i386/asm/elf.h:78: warning: ‘struct task_struct’ declared inside parameter list
arch/um/sys-i386/asm/elf.h:78: warning: its scope is only this definition or declaration, which is probably not what you want

I guess not many people build against i386 hosts anymore, so this
remained widely unnoticed.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-04-21 01:43:03 +02:00
Christoph Hellwig 698ba7b5a3 elf: kill USE_ELF_CORE_DUMP
Currently all architectures but microblaze unconditionally define
USE_ELF_CORE_DUMP.  The microblaze omission seems like an error to me, so
let's kill this ifdef and make sure we are the same everywhere.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <linux-arch@vger.kernel.org>
Cc: Michal Simek <michal.simek@petalogix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Roel Kluin b08cd961cc uml: bad macro expansion, parameter is member
`ELF_CORE_COPY_REGS(x, y)' will make expansions like:
`(y)[0] = (x)->x.gp[0]' but correct is `(y)[0] = (x)->regs.gp[0]'

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: WANG Cong <amwang@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:47 -07:00
WANG Cong 65bd6a9bc7 uml: remove useless comments
These comments are useless now, remove them.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:17 -07:00
Al Viro aa7bd94249 x86, um: get rid of header symlinks
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:22 -07:00