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#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <syslog.h>

#include "cookie.h"

static char const *priov[] = {
	[LOG_EMERG]	=	"EMERG:",
	[LOG_ALERT]	=	"ALERT:",
	[LOG_CRIT]	=	"CRIT:",
	[LOG_ERR]	=	"ERR:",
	[LOG_WARNING]	=	"WARNING:",
	[LOG_NOTICE]	=	"NOTICE:",
	[LOG_INFO]	=	"INFO:",
	[LOG_DEBUG]	=	"DEBUG:",
};

static ssize_t cookie_writer(void *cookie, char const *data, size_t leng)
{
	int prio = LOG_DEBUG, len;

	do {
		len = strlen(priov[prio]);
	} while (memcmp(data, priov[prio], len) && --prio >= 0);

	if (prio < 0) {
		prio = LOG_INFO;
	} else {
		data += len;
		leng -= len;
	}

	while (*data == ' ') {
		 ++data;
		--leng;
	}

	syslog(prio, "%.*s", (int) leng, data);

	return leng;
}

static cookie_io_functions_t cookie_log = {
	.write		=	cookie_writer,
};

void to_std_log(FILE **fp)
{
	setvbuf(*fp = fopencookie(NULL, "w", cookie_log), NULL, _IOLBF, 0);
}
e&id=966d2b04e070bc040319aaebfec09e0144dc3341'>tools/leds/.gitignore parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (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+
Diffstat (limited to 'tools/leds/.gitignore')