From: Tom Leete <tleete@mountain.net>
To: linux-kernel@vger.kernel.org
Subject: Race in fs/proc/generic.c:make_inode_number()
Date: Thu, 05 Apr 2001 01:14:52 -0400 [thread overview]
Message-ID: <3ACBFF4C.97AA345F@mountain.net> (raw)
Hello,
The proc_alloc_map bitfield is unprotected by any lock, and
find_first_zero_bit() is not atomic. Concurrent module loading can race
here.
static unsigned char proc_alloc_map[PROC_NDYNAMIC / 8];
static int make_inode_number(void)
{
int i = find_first_zero_bit((void *) proc_alloc_map, PROC_NDYNAMIC);
if (i<0 || i>=PROC_NDYNAMIC)
return -1;
set_bit(i, (void *) proc_alloc_map);
return PROC_DYNAMIC_FIRST + i;
}
Cheers,
Tom
--
The Daemons lurk and are dumb. -- Emerson
next reply other threads:[~2001-04-05 5:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-04-05 5:14 Tom Leete [this message]
2001-04-05 14:36 ` [PATCH] Re: Race in fs/proc/generic.c:make_inode_number() Tom Leete
2001-04-06 12:01 ` Maneesh Soni
2001-04-06 15:47 ` Tom Leete
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