/*
* debug.c - NTFS kernel debug support. Part of the Linux-NTFS project.
*
* Copyright (c) 2001-2004 Anton Altaparmakov
*
* This program/include file 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/include file 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 (in the main directory of the Linux-NTFS
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include "debug.h"
/**
* __ntfs_warning - output a warning to the syslog
* @function: name of function outputting the warning
* @sb: super block of mounted ntfs filesystem
* @fmt: warning string containing format specifications
* @...: a variable number of arguments specified in @fmt
*
* Outputs a warning to the syslog for the mounted ntfs filesystem described
* by @sb.
*
* @fmt and the corresponding @... is printf style format string containing
* the warning string and the corresponding format arguments, respectively.
*
* @function is the name of the function from which __ntfs_warning is being
* called.
*
* Note, you should be using debug.h::ntfs_warning(@sb, @fmt, @...) instead
* as this provides the @function parameter automatically.
*/
void __ntfs_warning(const char *function, const struct super_block *sb,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
int flen = 0;
#ifndef DEBUG
if (!printk_ratelimit())
return;
#endif
if (function)
flen = strlen(function);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
if (sb)
pr_warn("(device %s): %s(): %pV\n",
sb->s_id, flen ? function : "", &vaf);
else
pr_warn("%s(): %pV\n", flen ? function : "", &vaf);
va_end(args);
}
/**
* __ntfs_error - output an error to the syslog
* @function: name of function outputting the error
* @sb: super block of mounted ntfs filesystem
* @fmt: error string containing format specifications
* @...: a variable number of arguments specified in @fmt
*
* Outputs an error to the syslog for the mounted ntfs filesystem described
* by @sb.
*
* @fmt and the corresponding @... is printf style format string containing
* the error string and the corresponding format arguments, respectively.
*
* @function is the name of the function from which __ntfs_error is being
* called.
*
* Note, you should be using debug.h::ntfs_error(@sb, @fmt, @...) instead
* as this provides the @function parameter automatically.
*/
void __ntfs_error(const char *function, const struct super_block *sb,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
int flen = 0;
#ifndef DEBUG
if (!printk_ratelimit())
return;
#endif
if (function)
flen = strlen(function);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
if (sb)
pr_err("(device %s): %s(): %pV\n",
sb->s_id, flen ? function : "", &vaf);
else
pr_err("%s(): %pV\n", flen ? function : "", &vaf);
va_end(args);
}
#ifdef DEBUG
/* If 1, output debug messages, and if 0, don't. */
int debug_msgs = 0;
void __ntfs_debug(const char *file, int line, const char *function,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
int flen = 0;
if (!debug_msgs)
return;
if (function)
flen = strlen(function);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
pr_debug("(%s, %d): %s(): %pV", file, line, flen ? function : "", &vaf);
va_end(args);
}
/* Dump a runlist. Caller has to provide synchronisation for @rl. */
void ntfs_debug_dump_runlist(const runlist_element *rl)
{
int i;
const char *lcn_str[5] = { "LCN_HOLE ", "LCN_RL_NOT_MAPPED",
"LCN_ENOENT ", "LCN_unknown " };
if (!debug_msgs)
return;
pr_debug("Dumping runlist (values in hex):\n");
if (!rl) {
pr_debug("Run list not present.\n");
return;
}
pr_debug("VCN LCN Run length\n");
for (i = 0; ; i++) {
LCN lcn = (rl + i)->lcn;
if (lcn < (LCN)0) {
int index = -lcn - 1;
if (index > -LCN_ENOENT - 1)
index = 3;
pr_debug("%-16Lx %s %-16Lx%s\n",
(long long)(rl + i)->vcn, lcn_str[index],
(long long)(rl + i)->length,
(rl + i)->length ? "" :
" (runlist end)");
} else
pr_debug("%-16Lx %-16Lx %-16Lx%s\n",
(long long)(rl + i)->vcn,
(long long)(rl + i)->lcn,
(long long)(rl + i)->length,
(rl + i)->length ? "" :
" (runlist end)");
if (!(rl + i)->length)
break;
}
}
#endif
rdma_transport.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
| tree | 4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /net/rds/rdma_transport.h |
|---|
| parent | 1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff) |
|---|
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().
This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:
__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0
Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.
The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.
Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Reviewed-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+