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  1. 04 Mar, 2015 3 commits
  3. 03 Mar, 2015 17 commits
  5. 02 Mar, 2015 20 commits
    • Hans de Goede's avatar
      ideapad-laptop: Change Lenovo Yoga 2 series rfkill handling · f58ad536
      Hans de Goede authored 
      commit ce363c2b upstream.

It seems that the same problems which lead to adding an rfkill blacklist and
putting the Lenovo Yoga 2 11 on it are also present on the Lenovo Yoga 2 13
and Lenovo Yoga 2 Pro too:
https://bugzilla.redhat.com/show_bug.cgi?id=1021036
https://forums.lenovo.com/t5/Linux-Discussion/Yoga-2-13-not-Pro-Linux-Warning/m-p/1517612

Testing has shown that the firmware rfkill settings are persistent over
reboots. So blacklisting the driver is not good enough, if the wifi is blocked
at the firmware level the wifi needs to be explictly unblocked through the
ideapad-laptop interface.

And at least on the Lenovo Yoga 2 13 the VPCCMD_RF register which on devices
with hardware kill switch reports the hardware switch state, needs to be
explictly set to 1 (radio enabled / not blocked).

So this patch does 3 things to get proper rfkill handling on these models:

1) Instead of blacklisting the rfkill functionality, which means that people
with a firmware blocked wifi get stuck in that situation, ignore the value
reported by the not present hardware rfkill switch, as this is what is causing
ideapad-laptop to wrongly report all radios as hardware blocks. But do register
the rfkill interfaces so that the user can soft [un]block them.

2) On models without a hardware rfkill switch, explictly set VPCCMD_RF to 1

3) Drop the " 11" postfix from the dmi match string, as the entire Yoga 2
series is affected.

Yoga 2 11:
Reported-and-tested-by: default avatarVincent Gerris <vgerris@gmail.com>

Yoga 2 13:
Tested-by: madls05 <http://ubuntuforums.org/showthread.php?t=2215044>

Yoga 2 Pro:
Reported-and-tested-by: default avatarPeter F. Patel-Schneider <pfpschneider@gmail.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMatthew Garrett <matthew.garrett@nebula.com>
Cc: Gaudenz Steinlin <gaudenz@debian.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      f58ad536
    • Daniel Borkmann's avatar
      ipv6: mld: fix add_grhead skb_over_panic for devs with large MTUs · c562e7c8
      Daniel Borkmann authored 
      commit 4c672e4b upstream.

It has been reported that generating an MLD listener report on
devices with large MTUs (e.g. 9000) and a high number of IPv6
addresses can trigger a skb_over_panic():

skbuff: skb_over_panic: text:ffffffff80612a5d len:3776 put:20
head:ffff88046d751000 data:ffff88046d751010 tail:0xed0 end:0xec0
dev:port1
 ------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:100!
invalid opcode: 0000 [#1] SMP
Modules linked in: ixgbe(O)
CPU: 3 PID: 0 Comm: swapper/3 Tainted: G O 3.14.23+ #4
[...]
Call Trace:
 <IRQ>
 [<ffffffff80578226>] ? skb_put+0x3a/0x3b
 [<ffffffff80612a5d>] ? add_grhead+0x45/0x8e
 [<ffffffff80612e3a>] ? add_grec+0x394/0x3d4
 [<ffffffff80613222>] ? mld_ifc_timer_expire+0x195/0x20d
 [<ffffffff8061308d>] ? mld_dad_timer_expire+0x45/0x45
 [<ffffffff80255b5d>] ? call_timer_fn.isra.29+0x12/0x68
 [<ffffffff80255d16>] ? run_timer_softirq+0x163/0x182
 [<ffffffff80250e6f>] ? __do_softirq+0xe0/0x21d
 [<ffffffff8025112b>] ? irq_exit+0x4e/0xd3
 [<ffffffff802214bb>] ? smp_apic_timer_interrupt+0x3b/0x46
 [<ffffffff8063f10a>] ? apic_timer_interrupt+0x6a/0x70

mld_newpack() skb allocations are usually requested with dev->mtu
in size, since commit 72e09ad1 ("ipv6: avoid high order allocations")
we have changed the limit in order to be less likely to fail.

However, in MLD/IGMP code, we have some rather ugly AVAILABLE(skb)
macros, which determine if we may end up doing an skb_put() for
adding another record. To avoid possible fragmentation, we check
the skb's tailroom as skb->dev->mtu - skb->len, which is a wrong
assumption as the actual max allocation size can be much smaller.

The IGMP case doesn't have this issue as commit 57e1ab6e
("igmp: refine skb allocations") stores the allocation size in
the cb[].

Set a reserved_tailroom to make it fit into the MTU and use
skb_availroom() helper instead. This also allows to get rid of
igmp_skb_size().
Reported-by: default avatarWei Liu <lw1a2.jing@gmail.com>
Fixes: 72e09ad1 ("ipv6: avoid high order allocations")
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: David L Stevens <david.stevens@oracle.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      c562e7c8
    • Johan Hovold's avatar
      gpio: sysfs: fix gpio attribute-creation race · 58409c4e
      Johan Hovold authored 
      commit ebbeba12 upstream.

Fix attribute-creation race with userspace by using the default group
to create also the contingent gpio device attributes.

Fixes: d8f388d8 ("gpio: sysfs interface")
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
[ luis: backported to 3.16:
  - all changes in drivers/gpio/gpiolib.c
  - adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      58409c4e
    • Daniel Borkmann's avatar
      net: sctp: fix race for one-to-many sockets in sendmsg's auto associate · 11fd056b
      Daniel Borkmann authored 
      commit 2061dcd6 upstream.

I.e. one-to-many sockets in SCTP are not required to explicitly
call into connect(2) or sctp_connectx(2) prior to data exchange.
Instead, they can directly invoke sendmsg(2) and the SCTP stack
will automatically trigger connection establishment through 4WHS
via sctp_primitive_ASSOCIATE(). However, this in its current
implementation is racy: INIT is being sent out immediately (as
it cannot be bundled anyway) and the rest of the DATA chunks are
queued up for later xmit when connection is established, meaning
sendmsg(2) will return successfully. This behaviour can result
in an undesired side-effect that the kernel made the application
think the data has already been transmitted, although none of it
has actually left the machine, worst case even after close(2)'ing
the socket.

Instead, when the association from client side has been shut down
e.g. first gracefully through SCTP_EOF and then close(2), the
client could afterwards still receive the server's INIT_ACK due
to a connection with higher latency. This INIT_ACK is then considered
out of the blue and hence responded with ABORT as there was no
alive assoc found anymore. This can be easily reproduced f.e.
with sctp_test application from lksctp. One way to fix this race
is to wait for the handshake to actually complete.

The fix defers waiting after sctp_primitive_ASSOCIATE() and
sctp_primitive_SEND() succeeded, so that DATA chunks cooked up
from sctp_sendmsg() have already been placed into the output
queue through the side-effect interpreter, and therefore can then
be bundeled together with COOKIE_ECHO control chunks.

strace from example application (shortened):

socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP) = 3
sendmsg(3, {msg_name(28)={sa_family=AF_INET, sin_port=htons(8888), sin_addr=inet_addr("192.168.1.115")},
           msg_iov(1)=[{"hello", 5}], msg_controllen=0, msg_flags=0}, 0) = 5
sendmsg(3, {msg_name(28)={sa_family=AF_INET, sin_port=htons(8888), sin_addr=inet_addr("192.168.1.115")},
           msg_iov(1)=[{"hello", 5}], msg_controllen=0, msg_flags=0}, 0) = 5
sendmsg(3, {msg_name(28)={sa_family=AF_INET, sin_port=htons(8888), sin_addr=inet_addr("192.168.1.115")},
           msg_iov(1)=[{"hello", 5}], msg_controllen=0, msg_flags=0}, 0) = 5
sendmsg(3, {msg_name(28)={sa_family=AF_INET, sin_port=htons(8888), sin_addr=inet_addr("192.168.1.115")},
           msg_iov(1)=[{"hello", 5}], msg_controllen=0, msg_flags=0}, 0) = 5
sendmsg(3, {msg_name(28)={sa_family=AF_INET, sin_port=htons(8888), sin_addr=inet_addr("192.168.1.115")},
           msg_iov(0)=[], msg_controllen=48, {cmsg_len=48, cmsg_level=0x84 /* SOL_??? */, cmsg_type=, ...},
           msg_flags=0}, 0) = 0 // graceful shutdown for SOCK_SEQPACKET via SCTP_EOF
close(3) = 0

tcpdump before patch (fooling the application):

22:33:36.306142 IP 192.168.1.114.41462 > 192.168.1.115.8888: sctp (1) [INIT] [init tag: 3879023686] [rwnd: 106496] [OS: 10] [MIS: 65535] [init TSN: 3139201684]
22:33:36.316619 IP 192.168.1.115.8888 > 192.168.1.114.41462: sctp (1) [INIT ACK] [init tag: 3345394793] [rwnd: 106496] [OS: 10] [MIS: 10] [init TSN: 3380109591]
22:33:36.317600 IP 192.168.1.114.41462 > 192.168.1.115.8888: sctp (1) [ABORT]

tcpdump after patch:

14:28:58.884116 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [INIT] [init tag: 438593213] [rwnd: 106496] [OS: 10] [MIS: 65535] [init TSN: 3092969729]
14:28:58.888414 IP 192.168.1.115.8888 > 192.168.1.114.35846: sctp (1) [INIT ACK] [init tag: 381429855] [rwnd: 106496] [OS: 10] [MIS: 10] [init TSN: 2141904492]
14:28:58.888638 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [COOKIE ECHO] , (2) [DATA] (B)(E) [TSN: 3092969729] [...]
14:28:58.893278 IP 192.168.1.115.8888 > 192.168.1.114.35846: sctp (1) [COOKIE ACK] , (2) [SACK] [cum ack 3092969729] [a_rwnd 106491] [#gap acks 0] [#dup tsns 0]
14:28:58.893591 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [DATA] (B)(E) [TSN: 3092969730] [...]
14:28:59.096963 IP 192.168.1.115.8888 > 192.168.1.114.35846: sctp (1) [SACK] [cum ack 3092969730] [a_rwnd 106496] [#gap acks 0] [#dup tsns 0]
14:28:59.097086 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [DATA] (B)(E) [TSN: 3092969731] [...] , (2) [DATA] (B)(E) [TSN: 3092969732] [...]
14:28:59.103218 IP 192.168.1.115.8888 > 192.168.1.114.35846: sctp (1) [SACK] [cum ack 3092969732] [a_rwnd 106486] [#gap acks 0] [#dup tsns 0]
14:28:59.103330 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [SHUTDOWN]
14:28:59.107793 IP 192.168.1.115.8888 > 192.168.1.114.35846: sctp (1) [SHUTDOWN ACK]
14:28:59.107890 IP 192.168.1.114.35846 > 192.168.1.115.8888: sctp (1) [SHUTDOWN COMPLETE]

Looks like this bug is from the pre-git history museum. ;)

Fixes: 08707d54 ("lksctp-2_5_31-0_5_1.patch")
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Acked-by: default avatarVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      11fd056b
    • Alexander Duyck's avatar
      fib_trie: Fix /proc/net/fib_trie when CONFIG_IP_MULTIPLE_TABLES is not defined · 952a63d1
      Alexander Duyck authored 
      commit a5a519b2 upstream.

In recent testing I had disabled CONFIG_IP_MULTIPLE_TABLES and as a result
when I ran "cat /proc/net/fib_trie" the main trie was displayed multiple
times.  I found that the problem line of code was in the function
fib_trie_seq_next.  Specifically the line below caused the indexes to go in
the opposite direction of our traversal:

	h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);

This issue was that the RT tables are defined such that RT_TABLE_LOCAL is ID
255, while it is located at TABLE_LOCAL_INDEX of 0, and RT_TABLE_MAIN is 254
with a TABLE_MAIN_INDEX of 1.  This means that the above line will return 1
for the local table and 0 for main.  The result is that fib_trie_seq_next
will return NULL at the end of the local table, fib_trie_seq_start will
return the start of the main table, and then fib_trie_seq_next will loop on
main forever as h will always return 0.

The fix for this is to reverse the ordering of the two tables.  It has the
advantage of making it so that the tables now print in the same order
regardless of if multiple tables are enabled or not.  In order to make the
definition consistent with the multiple tables case I simply masked the to
RT_TABLE_XXX values by (FIB_TABLE_HASHSZ - 1).  This way the two table
layouts should always stay consistent.

Fixes: 93456b6d ("[IPV4]: Unify access to the routing tables")
Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      952a63d1
    • Seth Forshee's avatar
      HID: i2c-hid: Limit reads to wMaxInputLength bytes for input events · 06edf928
      Seth Forshee authored 
      commit 6d00f37e upstream.

d1c7e29e (HID: i2c-hid: prevent buffer overflow in early IRQ)
changed hid_get_input() to read ihid->bufsize bytes, which can be
more than wMaxInputLength. This is the case with the Dell XPS 13
9343, and it is causing events to be missed. In some cases the
missed events are releases, which can cause the cursor to jump or
freeze, among other problems. Limit the number of bytes read to
min(wMaxInputLength, ihid->bufsize) to prevent such problems.

Fixes: d1c7e29e "HID: i2c-hid: prevent buffer overflow in early IRQ"
Signed-off-by: default avatarSeth Forshee <seth.forshee@canonical.com>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      06edf928
    • Sasha Levin's avatar
      net: rds: use correct size for max unacked packets and bytes · 065f3735
      Sasha Levin authored 
      commit db27ebb1 upstream.

Max unacked packets/bytes is an int while sizeof(long) was used in the
sysctl table.

This means that when they were getting read we'd also leak kernel memory
to userspace along with the timeout values.
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      065f3735
    • Sasha Levin's avatar
      net: llc: use correct size for sysctl timeout entries · 42182789
      Sasha Levin authored 
      commit 6b8d9117 upstream.

The timeout entries are sizeof(int) rather than sizeof(long), which
means that when they were getting read we'd also leak kernel memory
to userspace along with the timeout values.
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      42182789
    • Andrew Elble's avatar
      GFS2: Fix crash during ACL deletion in acl max entry check in gfs2_set_acl() · 9e2feaeb
      Andrew Elble authored 
      commit 27870207 upstream.

Fixes: e01580bf ("gfs2: use generic posix ACL infrastructure")
Reported-by: default avatarEric Meddaugh <etmsys@rit.edu>
Tested-by: default avatarEric Meddaugh <etmsys@rit.edu>
Signed-off-by: default avatarAndrew Elble <aweits@rit.edu>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9e2feaeb
    • Dan Carpenter's avatar
      ALSA: off by one bug in snd_riptide_joystick_probe() · 3a87ac14
      Dan Carpenter authored 
      commit e4940626 upstream.

The problem here is that we check:

	if (dev >= SNDRV_CARDS)

Then we increment "dev".

       if (!joystick_port[dev++])

Then we use it as an offset into a array with SNDRV_CARDS elements.

	if (!request_region(joystick_port[dev], 8, "Riptide gameport")) {

This has 3 effects:
1) If you use the module option to specify the joystick port then it has
   to be shifted one space over.
2) The wrong error message will be printed on failure if you have over
   32 cards.
3) Static checkers will correctly complain that are off by one.

Fixes: db1005ec ('ALSA: riptide - Fix joystick resource handling')
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      3a87ac14
    • Uwe Kleine-König's avatar
      pinctrl: pinctrl-imx: don't use invalid value of conf_reg · dd89ea7a
      Uwe Kleine-König authored 
      commit 4ff0f034 upstream.

The right check for conf_reg to be invalid it testing against -1 not 0
as is done in the rest of the driver.

This fixes an oops that can be triggered by:

	cat /sys/kernel/debug/pinctrl/43fac000.iomuxc/*

Fixes: ae75ff81 ("pinctrl: pinctrl-imx: add imx pinctrl core driver")
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
[ luis: backported to 3.16:
  - file rename: drivers/pinctrl/freescale/pinctrl-imx.c ->
    drivers/pinctrl/pinctrl-imx.c ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      dd89ea7a
    • Gavin Shan's avatar
      powerpc/kernel: Avoid memory corruption at early stage · 79e43709
      Gavin Shan authored 
      commit 6f20e7f2 upstream.

When calling to early_setup(), we pick "boot_paca" up for the master CPU
and initialize that with initialise_paca(). At that point, the SLB
shadow buffer isn't populated yet. Updating the SLB shadow buffer should
corrupt what we had in physical address 0 where the trap instruction is
usually stored.

This hasn't been observed to cause any trouble in practice, but is
obviously fishy.

Fixes: 6f4441ef ("powerpc: Dynamically allocate slb_shadow from memblock")
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      79e43709
    • Sergei Shtylyov's avatar
      clk-gate: fix bit # check in clk_register_gate() · e99423f7
      Sergei Shtylyov authored 
      commit 2e9dcdae upstream.

In case CLK_GATE_HIWORD_MASK flag is passed to clk_register_gate(), the bit #
should be no higher than 15, however the corresponding check is obviously off-
by-one.

Fixes: 04577994 ("clk: gate: add CLK_GATE_HIWORD_MASK")
Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: default avatarMichael Turquette <mturquette@linaro.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      e99423f7
    • Dan Carpenter's avatar
      efi: Small leak on error in runtime map code · 89639edd
      Dan Carpenter authored 
      commit 86d68a58 upstream.

The "> 0" here should ">= 0" so we free map_entries[0].

Fixes: 926172d4 ('efi: Export EFI runtime memory mapping to sysfs')
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Acked-by: default avatarDave Young <dyoung@redhat.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      89639edd
    • Geert Uytterhoeven's avatar
      gpio: rcar: Fix error path for devm_kzalloc() failure · 62503026
      Geert Uytterhoeven authored 
      commit 7d82bf34 upstream.

If the call to devm_kzalloc() fails, nothing must be cleant up.
This was missed before because gpio_rcar_probe() had a "return"
statement after the first "goto err0".
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Fixes: df0c6c80 ("gpio: rcar: Add minimal runtime PM support")
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      62503026
    • Lars-Peter Clausen's avatar
      ASoC: mioa701_wm9713: Fix speaker event · 50992849
      Lars-Peter Clausen authored 
      commit 7331ea47 upstream.

Commit f6b2a045 ("ASoC: pxa: mioa701_wm9713: Convert to table based DAPM
setup") converted the driver to register the board level DAPM elements with
the card's DAPM context rather than the CODEC's DAPM context. The change
overlooked that the speaker widget event callback accesses the widget's
codec field which is only valid if the widget has been registered in a CODEC
DAPM context. This patch modifies the callback to take an alternative route
to get the CODEC.

Fixes: f6b2a045 ("ASoC: pxa: mioa701_wm9713: Convert to table based DAPM
setup")
Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      50992849
    • Al Viro's avatar
      autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation · 2321de6e
      Al Viro authored 
      commit 0a280962 upstream.

X-Coverup: just ask spender
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      2321de6e
    • Al Viro's avatar
      procfs: fix race between symlink removals and traversals · 48a6aba3
      Al Viro authored 
      commit 7e0e953b upstream.

use_pde()/unuse_pde() in ->follow_link()/->put_link() resp.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      48a6aba3
    • Al Viro's avatar
      debugfs: leave freeing a symlink body until inode eviction · 67083b7b
      Al Viro authored 
      commit 0db59e59 upstream.

As it is, we have debugfs_remove() racing with symlink traversals.
Supply ->evict_inode() and do freeing there - inode will remain
pinned until we are done with the symlink body.

And rip the idiocy with checking if dentry is positive right after
we'd verified debugfs_positive(), which is a stronger check...
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      67083b7b
    • Thadeu Lima de Souza Cascardo's avatar
      blk-throttle: check stats_cpu before reading it from sysfs · ad9ea48d
      Thadeu Lima de Souza Cascardo authored 
      commit 045c47ca upstream.

When reading blkio.throttle.io_serviced in a recently created blkio
cgroup, it's possible to race against the creation of a throttle policy,
which delays the allocation of stats_cpu.

Like other functions in the throttle code, just checking for a NULL
stats_cpu prevents the following oops caused by that race.

[ 1117.285199] Unable to handle kernel paging request for data at address 0x7fb4d0020
[ 1117.285252] Faulting instruction address: 0xc0000000003efa2c
[ 1137.733921] Oops: Kernel access of bad area, sig: 11 [#1]
[ 1137.733945] SMP NR_CPUS=2048 NUMA PowerNV
[ 1137.734025] Modules linked in: bridge stp llc kvm_hv kvm binfmt_misc autofs4
[ 1137.734102] CPU: 3 PID: 5302 Comm: blkcgroup Not tainted 3.19.0 #5
[ 1137.734132] task: c000000f1d188b00 ti: c000000f1d210000 task.ti: c000000f1d210000
[ 1137.734167] NIP: c0000000003efa2c LR: c0000000003ef9f0 CTR: c0000000003ef980
[ 1137.734202] REGS: c000000f1d213500 TRAP: 0300   Not tainted  (3.19.0)
[ 1137.734230] MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI>  CR: 42008884  XER: 20000000
[ 1137.734325] CFAR: 0000000000008458 DAR: 00000007fb4d0020 DSISR: 40000000 SOFTE: 0
GPR00: c0000000003ed3a0 c000000f1d213780 c000000000c59538 0000000000000000
GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000
GPR08: ffffffffffffffff 00000007fb4d0020 00000007fb4d0000 c000000000780808
GPR12: 0000000022000888 c00000000fdc0d80 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 000001003e120200 c000000f1d5b0cc0 0000000000000200 0000000000000000
GPR24: 0000000000000001 c000000000c269e0 0000000000000020 c000000f1d5b0c80
GPR28: c000000000ca3a08 c000000000ca3dec c000000f1c667e00 c000000f1d213850
[ 1137.734886] NIP [c0000000003efa2c] .tg_prfill_cpu_rwstat+0xac/0x180
[ 1137.734915] LR [c0000000003ef9f0] .tg_prfill_cpu_rwstat+0x70/0x180
[ 1137.734943] Call Trace:
[ 1137.734952] [c000000f1d213780] [d000000005560520] 0xd000000005560520 (unreliable)
[ 1137.734996] [c000000f1d2138a0] [c0000000003ed3a0] .blkcg_print_blkgs+0xe0/0x1a0
[ 1137.735039] [c000000f1d213960] [c0000000003efb50] .tg_print_cpu_rwstat+0x50/0x70
[ 1137.735082] [c000000f1d2139e0] [c000000000104b48] .cgroup_seqfile_show+0x58/0x150
[ 1137.735125] [c000000f1d213a70] [c0000000002749dc] .kernfs_seq_show+0x3c/0x50
[ 1137.735161] [c000000f1d213ae0] [c000000000218630] .seq_read+0xe0/0x510
[ 1137.735197] [c000000f1d213bd0] [c000000000275b04] .kernfs_fop_read+0x164/0x200
[ 1137.735240] [c000000f1d213c80] [c0000000001eb8e0] .__vfs_read+0x30/0x80
[ 1137.735276] [c000000f1d213cf0] [c0000000001eb9c4] .vfs_read+0x94/0x1b0
[ 1137.735312] [c000000f1d213d90] [c0000000001ebb38] .SyS_read+0x58/0x100
[ 1137.735349] [c000000f1d213e30] [c000000000009218] syscall_exit+0x0/0x98
[ 1137.735383] Instruction dump:
[ 1137.735405] 7c6307b4 7f891800 409d00b8 60000000 60420000 3d420004 392a63b0 786a1f24
[ 1137.735471] 7d49502a e93e01c8 7d495214 7d2ad214 <7cead02a> e9090008 e9490010 e9290018

And here is one code that allows to easily reproduce this, although this
has first been found by running docker.

void run(pid_t pid)
{
	int n;
	int status;
	int fd;
	char *buffer;
	buffer = memalign(BUFFER_ALIGN, BUFFER_SIZE);
	n = snprintf(buffer, BUFFER_SIZE, "%d\n", pid);
	fd = open(CGPATH "/test/tasks", O_WRONLY);
	write(fd, buffer, n);
	close(fd);
	if (fork() > 0) {
		fd = open("/dev/sda", O_RDONLY | O_DIRECT);
		read(fd, buffer, 512);
		close(fd);
		wait(&status);
	} else {
		fd = open(CGPATH "/test/blkio.throttle.io_serviced", O_RDONLY);
		n = read(fd, buffer, BUFFER_SIZE);
		close(fd);
	}
	free(buffer);
	exit(0);
}

void test(void)
{
	int status;
	mkdir(CGPATH "/test", 0666);
	if (fork() > 0)
		wait(&status);
	else
		run(getpid());
	rmdir(CGPATH "/test");
}

int main(int argc, char **argv)
{
	int i;
	for (i = 0; i < NR_TESTS; i++)
		test();
	return 0;
}
Reported-by: default avatarRicardo Marin Matinata <rmm@br.ibm.com>
Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      ad9ea48d
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