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mm, aout: handle vm_brk failures

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vm_brk is allowed to fail but load_aout_binary simply ignores the error
and happily continues.  I haven't noticed any problem from that in real
life but later patches will make the failure more likely because vm_brk
will become killable (resp.  mmap_sem for write waiting will become
killable) so we should be more careful now.

The error handling should be quite straightforward because there are
calls to vm_mmap which check the error properly already.  The only
notable exception is set_brk which is called after beyond_if label.  But
nothing indicates that we cannot move it above set_binfmt as the two do
not depend on each other and fail before we do set_binfmt and alter
reference counting.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko 2016-05-23 16:25:36 -07:00 committed by Linus Torvalds
parent ae79878356
commit 864778b154
2 changed files with 24 additions and 11 deletions
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24
arch/x86/ia32/ia32_aout.c
View File

@ -116,13 +116,13 @@ static struct linux_binfmt aout_format = {
.min_coredump = PAGE_SIZE
};
static void set_brk(unsigned long start, unsigned long end)
static unsigned long set_brk(unsigned long start, unsigned long end)
{
start = PAGE_ALIGN(start);
end = PAGE_ALIGN(end);
if (end <= start)
return;
vm_brk(start, end - start);
return start;
return vm_brk(start, end - start);
}
#ifdef CONFIG_COREDUMP
@ -349,7 +349,10 @@ static int load_aout_binary(struct linux_binprm *bprm)
#endif
if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
if (IS_ERR_VALUE(error))
return error;
read_code(bprm->file, N_TXTADDR(ex), fd_offset,
ex.a_text+ex.a_data);
goto beyond_if;
@ -372,10 +375,13 @@ static int load_aout_binary(struct linux_binprm *bprm)
if (error != N_DATADDR(ex))
return error;
}
beyond_if:
set_binfmt(&aout_format);
set_brk(current->mm->start_brk, current->mm->brk);
beyond_if:
error = set_brk(current->mm->start_brk, current->mm->brk);
if (IS_ERR_VALUE(error))
return error;
set_binfmt(&aout_format);
current->mm->start_stack =
(unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
@ -434,7 +440,9 @@ static int load_aout_library(struct file *file)
error_time = jiffies;
}
#endif
vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
if (IS_ERR_VALUE(retval))
goto out;
read_code(file, start_addr, N_TXTOFF(ex),
ex.a_text + ex.a_data);

11
fs/binfmt_aout.c
View File

@ -297,7 +297,10 @@ static int load_aout_binary(struct linux_binprm * bprm)
}
if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
if (IS_ERR_VALUE(error))
return error;
read_code(bprm->file, N_TXTADDR(ex), fd_offset,
ex.a_text + ex.a_data);
goto beyond_if;
@ -378,8 +381,10 @@ static int load_aout_library(struct file *file)
"N_TXTOFF is not page aligned. Please convert library: %pD\n",
file);
}
vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
if (IS_ERR_VALUE(retval))
goto out;
read_code(file, start_addr, N_TXTOFF(ex),
ex.a_text + ex.a_data);
retval = 0;