#
# SCTP configuration
#

menuconfig IP_SCTP
	tristate "The SCTP Protocol"
	depends on INET
	depends on IPV6 || IPV6=n
	select CRYPTO
	select CRYPTO_HMAC
	select CRYPTO_SHA1
	select LIBCRC32C
	---help---
	  Stream Control Transmission Protocol

	  From RFC 2960 <http://www.ietf.org/rfc/rfc2960.txt>.

	  "SCTP is a reliable transport protocol operating on top of a
	  connectionless packet network such as IP.  It offers the following
	  services to its users:

	  -- acknowledged error-free non-duplicated transfer of user data,
	  -- data fragmentation to conform to discovered path MTU size,
	  -- sequenced delivery of user messages within multiple streams,
	  with an option for order-of-arrival delivery of individual user
	  messages,
	  -- optional bundling of multiple user messages into a single SCTP
	  packet, and
	  -- network-level fault tolerance through supporting of multi-
	  homing at either or both ends of an association."

	  To compile this protocol support as a module, choose M here: the
	  module will be called sctp. Debug messages are handeled by the
	  kernel's dynamic debugging framework.

	  If in doubt, say N.

if IP_SCTP

config NET_SCTPPROBE
	tristate "SCTP: Association probing"
        depends on PROC_FS && KPROBES
        ---help---
        This module allows for capturing the changes to SCTP association
        state in response to incoming packets. It is used for debugging
        SCTP congestion control algorithms. If you don't understand
        what was just said, you don't need it: say N.

        To compile this code as a module, choose M here: the
        module will be called sctp_probe.

config SCTP_DBG_OBJCNT
	bool "SCTP: Debug object counts"
	depends on PROC_FS
	help
	  If you say Y, this will enable debugging support for counting the 
	  type of objects that are currently allocated.  This is useful for 
	  identifying memory leaks. This debug information can be viewed by
	  'cat /proc/net/sctp/sctp_dbg_objcnt'

	  If unsure, say N
choice
	prompt "Default SCTP cookie HMAC encoding"
	default SCTP_DEFAULT_COOKIE_HMAC_MD5
	help
	  This option sets the default sctp cookie hmac algorithm
	  when in doubt select 'md5'

config SCTP_DEFAULT_COOKIE_HMAC_MD5
	bool "Enable optional MD5 hmac cookie generation"
	help
	  Enable optional MD5 hmac based SCTP cookie generation
	select SCTP_COOKIE_HMAC_MD5

config SCTP_DEFAULT_COOKIE_HMAC_SHA1
	bool "Enable optional SHA1 hmac cookie generation"
	help
	  Enable optional SHA1 hmac based SCTP cookie generation
	select SCTP_COOKIE_HMAC_SHA1

config SCTP_DEFAULT_COOKIE_HMAC_NONE
	bool "Use no hmac alg in SCTP cookie generation"
	help
	  Use no hmac algorithm in SCTP cookie generation

endchoice

config SCTP_COOKIE_HMAC_MD5
	bool "Enable optional MD5 hmac cookie generation"
	help
	  Enable optional MD5 hmac based SCTP cookie generation
	select CRYPTO_HMAC if SCTP_COOKIE_HMAC_MD5
	select CRYPTO_MD5 if SCTP_COOKIE_HMAC_MD5

config SCTP_COOKIE_HMAC_SHA1
	bool "Enable optional SHA1 hmac cookie generation"
	help
	  Enable optional SHA1 hmac based SCTP cookie generation
	select CRYPTO_HMAC if SCTP_COOKIE_HMAC_SHA1
	select CRYPTO_SHA1 if SCTP_COOKIE_HMAC_SHA1

config INET_SCTP_DIAG
	depends on INET_DIAG
	def_tristate INET_DIAG


endif # IP_SCTP
672d5a37e'/><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>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/pci/rme9652?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/pci/rme9652?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/pci/rme9652?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>sound/pci/rme9652</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/pci/rme9652?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/pci/rme9652?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'sound/pci/rme9652')</div><table summary='diffstat' class='diffstat'>