/*
 * NOTE: This example is works on x86 and powerpc.
 * Here's a sample kernel module showing the use of kprobes to dump a
 * stack trace and selected registers when _do_fork() is called.
 *
 * For more information on theory of operation of kprobes, see
 * Documentation/kprobes.txt
 *
 * You will see the trace data in /var/log/messages and on the console
 * whenever _do_fork() is invoked to create a new process.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kprobes.h>

#define MAX_SYMBOL_LEN	64
static char symbol[MAX_SYMBOL_LEN] = "_do_fork";
module_param_string(symbol, symbol, sizeof(symbol), 0644);

/* For each probe you need to allocate a kprobe structure */
static struct kprobe kp = {
	.symbol_name	= symbol,
};

/* kprobe pre_handler: called just before the probed instruction is executed */
static int handler_pre(struct kprobe *p, struct pt_regs *regs)
{
#ifdef CONFIG_X86
	pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
		p->symbol_name, p->addr, regs->ip, regs->flags);
#endif
#ifdef CONFIG_PPC
	pr_info("<%s> pre_handler: p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
		p->symbol_name, p->addr, regs->nip, regs->msr);
#endif
#ifdef CONFIG_MIPS
	pr_info("<%s> pre_handler: p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
		p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status);
#endif
#ifdef CONFIG_TILEGX
	pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx, ex1 = 0x%lx\n",
		p->symbol_name, p->addr, regs->pc, regs->ex1);
#endif
#ifdef CONFIG_ARM64
	pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx,"
			" pstate = 0x%lx\n",
		p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate);
#endif

	/* A dump_stack() here will give a stack backtrace */
	return 0;
}

/* kprobe post_handler: called after the probed instruction is executed */
static void handler_post(struct kprobe *p, struct pt_regs *regs,
				unsigned long flags)
{
#ifdef CONFIG_X86
	pr_info("<%s> post_handler: p->addr = 0x%p, flags = 0x%lx\n",
		p->symbol_name, p->addr, regs->flags);
#endif
#ifdef CONFIG_PPC
	pr_info("<%s> post_handler: p->addr = 0x%p, msr = 0x%lx\n",
		p->symbol_name, p->addr, regs->msr);
#endif
#ifdef CONFIG_MIPS
	pr_info("<%s> post_handler: p->addr = 0x%p, status = 0x%lx\n",
		p->symbol_name, p->addr, regs->cp0_status);
#endif
#ifdef CONFIG_TILEGX
	pr_info("<%s> post_handler: p->addr = 0x%p, ex1 = 0x%lx\n",
		p->symbol_name, p->addr, regs->ex1);
#endif
#ifdef CONFIG_ARM64
	pr_info("<%s> post_handler: p->addr = 0x%p, pstate = 0x%lx\n",
		p->symbol_name, p->addr, (long)regs->pstate);
#endif
}

/*
 * fault_handler: this is called if an exception is generated for any
 * instruction within the pre- or post-handler, or when Kprobes
 * single-steps the probed instruction.
 */
static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
{
	pr_info("fault_handler: p->addr = 0x%p, trap #%dn", p->addr, trapnr);
	/* Return 0 because we don't handle the fault. */
	return 0;
}

static int __init kprobe_init(void)
{
	int ret;
	kp.pre_handler = handler_pre;
	kp.post_handler = handler_post;
	kp.fault_handler = handler_fault;

	ret = register_kprobe(&kp);
	if (ret < 0) {
		pr_err("register_kprobe failed, returned %d\n", ret);
		return ret;
	}
	pr_info("Planted kprobe at %p\n", kp.addr);
	return 0;
}

static void __exit kprobe_exit(void)
{
	unregister_kprobe(&kp);
	pr_info("kprobe at %p unregistered\n", kp.addr);
}

module_init(kprobe_init)
module_exit(kprobe_exit)
MODULE_LICENSE("GPL");
0980552fe508c'>selftests</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c'>ftrace</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='433e19cf33d34bb6751c874a9c00980552fe508c'/><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>Dexuan Cui &lt;decui@microsoft.com&gt;</td><td class='right'>2017-01-28 11:46:02 -0700</td></tr>
<tr><th>committer</th><td>Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;</td><td class='right'>2017-01-31 10:59:48 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c'>433e19cf33d34bb6751c874a9c00980552fe508c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/testing/selftests/ftrace?id=433e19cf33d34bb6751c874a9c00980552fe508c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c'>ce6547ef2987fbb289fa28f03536328a42781651</a> /<a href='/cgit.cgi/linux/net-next.git/tree/tools/testing/selftests/ftrace?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c'>tools/testing/selftests/ftrace</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace?h=nds-private-remove&amp;id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>191e885a2e130e639bb0c8ee350d7047294f2ce6</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/testing/selftests/ftrace?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c&amp;id2=191e885a2e130e639bb0c8ee350d7047294f2ce6'>diff</a>)</td></tr></table>
<div class='commit-subject'>Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()</div><div class='commit-msg'>Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz &lt; pending_sz"
when making the signal decision.

As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.

This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).

Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")

Signed-off-by: Dexuan Cui &lt;decui@microsoft.com&gt;
Reported-by: Rolf Neugebauer &lt;rolf.neugebauer@docker.com&gt;
Tested-by: Rolf Neugebauer &lt;rolf.neugebauer@docker.com&gt;
Cc: "K. Y. Srinivasan" &lt;kys@microsoft.com&gt;
Cc: Haiyang Zhang &lt;haiyangz@microsoft.com&gt;
Cc: Stephen Hemminger &lt;sthemmin@microsoft.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: K. Y. Srinivasan &lt;kys@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=433e19cf33d34bb6751c874a9c00980552fe508c'>Diffstat</a> (limited to 'tools/testing/selftests/ftrace')</div><table summary='diffstat' class='diffstat'>