#undef TRACE_SYSTEM
#define TRACE_SYSTEM migrate

#if !defined(_TRACE_MIGRATE_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_MIGRATE_H

#include <linux/tracepoint.h>

#define MIGRATE_MODE						\
	EM( MIGRATE_ASYNC,	"MIGRATE_ASYNC")		\
	EM( MIGRATE_SYNC_LIGHT,	"MIGRATE_SYNC_LIGHT")		\
	EMe(MIGRATE_SYNC,	"MIGRATE_SYNC")


#define MIGRATE_REASON						\
	EM( MR_COMPACTION,	"compaction")			\
	EM( MR_MEMORY_FAILURE,	"memory_failure")		\
	EM( MR_MEMORY_HOTPLUG,	"memory_hotplug")		\
	EM( MR_SYSCALL,		"syscall_or_cpuset")		\
	EM( MR_MEMPOLICY_MBIND,	"mempolicy_mbind")		\
	EM( MR_NUMA_MISPLACED,	"numa_misplaced")		\
	EMe(MR_CMA,		"cma")

/*
 * First define the enums in the above macros to be exported to userspace
 * via TRACE_DEFINE_ENUM().
 */
#undef EM
#undef EMe
#define EM(a, b)	TRACE_DEFINE_ENUM(a);
#define EMe(a, b)	TRACE_DEFINE_ENUM(a);

MIGRATE_MODE
MIGRATE_REASON

/*
 * Now redefine the EM() and EMe() macros to map the enums to the strings
 * that will be printed in the output.
 */
#undef EM
#undef EMe
#define EM(a, b)	{a, b},
#define EMe(a, b)	{a, b}

TRACE_EVENT(mm_migrate_pages,

	TP_PROTO(unsigned long succeeded, unsigned long failed,
		 enum migrate_mode mode, int reason),

	TP_ARGS(succeeded, failed, mode, reason),

	TP_STRUCT__entry(
		__field(	unsigned long,		succeeded)
		__field(	unsigned long,		failed)
		__field(	enum migrate_mode,	mode)
		__field(	int,			reason)
	),

	TP_fast_assign(
		__entry->succeeded	= succeeded;
		__entry->failed		= failed;
		__entry->mode		= mode;
		__entry->reason		= reason;
	),

	TP_printk("nr_succeeded=%lu nr_failed=%lu mode=%s reason=%s",
		__entry->succeeded,
		__entry->failed,
		__print_symbolic(__entry->mode, MIGRATE_MODE),
		__print_symbolic(__entry->reason, MIGRATE_REASON))
);

TRACE_EVENT(mm_numa_migrate_ratelimit,

	TP_PROTO(struct task_struct *p, int dst_nid, unsigned long nr_pages),

	TP_ARGS(p, dst_nid, nr_pages),

	TP_STRUCT__entry(
		__array(	char,		comm,	TASK_COMM_LEN)
		__field(	pid_t,		pid)
		__field(	int,		dst_nid)
		__field(	unsigned long,	nr_pages)
	),

	TP_fast_assign(
		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
		__entry->pid		= p->pid;
		__entry->dst_nid	= dst_nid;
		__entry->nr_pages	= nr_pages;
	),

	TP_printk("comm=%s pid=%d dst_nid=%d nr_pages=%lu",
		__entry->comm,
		__entry->pid,
		__entry->dst_nid,
		__entry->nr_pages)
);
#endif /* _TRACE_MIGRATE_H */

/* This part must be outside protection */
#include <trace/define_trace.h>
e='range'>range</option>
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<input class='txt' type='search' size='10' name='q' value=''/>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs?id=966d2b04e070bc040319aaebfec09e0144dc3341'>fs</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs/nfsd?id=966d2b04e070bc040319aaebfec09e0144dc3341'>nfsd</a>/<a href='/cgit.cgi/linux/net-next.git/commit/fs/nfsd/xdr.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>xdr.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='966d2b04e070bc040319aaebfec09e0144dc3341'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;</td><td class='right'>2017-01-28 06:42:20 -0600</td></tr>
<tr><th>committer</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-28 07:49:42 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/fs/nfsd/xdr.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/fs/nfsd/xdr.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>4b96156e3d1dd4dfd6039b7c219c9dc4616da52d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/fs/nfsd/xdr.h?id=966d2b04e070bc040319aaebfec09e0144dc3341'>fs/nfsd/xdr.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/fs/nfsd/xdr.h?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/fs/nfsd/xdr.h?id=966d2b04e070bc040319aaebfec09e0144dc3341&amp;id2=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>diff</a>)</td></tr></table>
<div class='commit-subject'>percpu-refcount: fix reference leak during percpu-atomic transition</div><div class='commit-msg'>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 &lt;dougmill@linux.vnet.ibm.com&gt;
Reviewed-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>Diffstat</a> (limited to 'fs/nfsd/xdr.h')</div><table summary='diffstat' class='diffstat'>