The dirfragtree is lazily updated, it's not always accurate. Infinite
loops happens in following circumstance.

- client send request to read frag A
- frag A has been fragmented into frag B and C. So mds fills the reply
  with contents of frag B
- client wants to read next frag C. ceph_choose_frag(frag value of C)
  return frag A.

The fix is using previous readdir reply to calculate next readdir frag
when possible.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Support disabling automatic exclusive lock transfers to allow users
to be in charge of which node should own the lock while being able to
reuse exclusive lock's built-in blacklist/break-lock functionality.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

Right now it's just 0, but "no automatic exclusive lock transfers" mode
code will need -EROFS.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

Currently the exclusive lock is acquired only if the mapping is
writable, i.e. an image HEAD mapped in rw mode.  This means that we
don't acquire the lock for executing a read from a snapshot or an image
HEAD mapped in ro mode, even if lock_on_read is set.  This is somewhat
weird and inconsistent with "no automatic exclusive lock transfers"
mode, where the lock is acquired unconditionally.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

As we no longer release the lock before potentially raising BLACKLISTED
in rbd_reregister_watch(), the "either locked or blacklisted" assert in
rbd_queue_workfn() needs to go: we can be both locked and blacklisted
at that point now.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

In preparation for supporting set_cookie method (or rather set_cookie
fallback for older OSDs), store the lock cookie on lock and use it on
unlock instead of recalculating from rbd_dev->watch_cookie.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

Currently the lock_state is set to UNLOCKED (preventing further I/O),
but RELEASED_LOCK notification isn't sent.  Be consistent with userspace
and treat ceph_cls_unlock() errors as the image is unlocked.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

add_disk() takes an extra reference on disk->queue, which is put in
put_disk() -> disk_release().  Avoiding blk_cleanup_queue() (which also
puts the queue) until add_disk() sets GENHD_FL_UP works for the queue
itself, but leaks various queue internals.  Conditioning tag_set freeing
on GENHD_FL_UP is wrong too: all error paths after rbd_init_disk() leak
the tag_set.

Move the final "announce" steps out of rbd_dev_device_setup() so that
it can be unwound like any other function.  Leave "announce" steps to
do_rbd_add/remove().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

rbd_dev->disk tear down vs rbd_watch_cb() race shouldn't be a problem
anymore thanks to EXISTS and REMOVING checks in rbd_dev_update_size().
A similar race could occur on "rbd map", see commit 811c6688
("rbd: fix rbd map vs notify races").
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

... to simplify error handling in do_rbd_add().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

Currently, we don't have a real feedback mechanism in place for when we
start seeing buffered writeback errors. If writeback is failing, there
is nothing that prevents an application from continuing to dirty pages
that aren't being cleaned.

In the event that we're seeing write errors of any sort occur on an
inode, have the callback set a flag to force further writes to be
synchronous. When the next write succeeds, clear the flag to allow
buffered writeback to continue.

Since this is just a hint to the write submission mechanism, we only
take the i_ceph_lock when a lockless check shows that the flag needs to
be changed.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng” <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

This reverts commit b109eec6.

If I'm filling up a filesystem with this sort of command:

    $ dd if=/dev/urandom of=/mnt/cephfs/fillfile bs=2M oflag=sync

...then I'll eventually get back EIO on a write. Further calls
will give us ENOSPC.

I'm not sure what prompted this change, but I don't think it's what we
want to do. If writepages failed, we will have already set the mapping
error appropriately, and that's what gets reported by fsync() or
close().

__filemap_fdatawait_range however, does this:

	wait_on_page_writeback(page);
	if (TestClearPageError(page))
		ret = -EIO;

...and that -EIO ends up trumping the mapping's error if one exists.

When writepages fails, we only want to set the error in the mapping,
and not flag the individual pages.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng” <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Have the client store and update the osdc epoch_barrier when a cap
message comes in with one.

When sending cap messages, send the epoch barrier as well. This allows
clients to inform servers that their released caps may not be used until
a particular OSD map epoch.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng” <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Cephfs can get cap update requests that contain a new epoch barrier in
them. When that happens we want to pause all OSD traffic until the right
map epoch arrives.

Add an epoch_barrier field to ceph_osd_client that is protected by the
osdc->lock rwsem. When the barrier is set, and the current OSD map
epoch is below that, pause the request target when submitting the
request or when revisiting it. Add a way for upper layers (cephfs)
to update the epoch_barrier as well.

If we get a new map, compare the new epoch against the barrier before
kicking requests and request another map if the map epoch is still lower
than the one we want.

If we get a map with a full pool, or at quota condition, then set the
barrier to the current epoch value.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

When a Ceph volume hits capacity, a flag is set in the OSD map to
indicate that, and a new map is sprayed around the cluster. With cephfs
we want it to shut down any abortable requests that are in progress with
an -ENOSPC error as they'd just hang otherwise.

Add a new ceph_osdc_abort_on_full helper function to handle this. It
will first check whether there is an out-of-space condition in the
cluster and then walk the tree and abort any request that has
r_abort_on_full set with a -ENOSPC error. Call this new function
directly whenever we get a new OSD map.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Usually, when the osd map is flagged as full or the pool is at quota,
write requests just hang. This is not what we want for cephfs, where
it would be better to simply report -ENOSPC back to userland instead
of stalling.

If the caller knows that it will want an immediate error return instead
of blocking on a full or at-quota error condition then allow it to set a
flag to request that behavior.

Set that flag in ceph_osdc_new_request (since ceph.ko is the only caller),
and on any other write request from ceph.ko.

A later patch will deal with requests that were submitted before the new
map showing the full condition came in.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Nothing uses this anymore with the removal of the ack vs. commit code.
Remove the field and just encode zeroes into place in the request
encoding.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Current cephfs client uses string to indicate start position of
readdir. The string is last entry of previous readdir reply.
This approach does not work for seeky readdir because we can
not easily convert the new postion to a string. For seeky readdir,
mds needs to return dentries from the beginning. Client keeps
retrying if the reply does not contain the dentry it wants.

In current version of ceph, mds sorts CDentry in its cache in
hash order. Client also uses dentry hash to compose dir postion.
For seeky readdir, if client passes the hash part of dir postion
to mds. mds can avoid replying useless dentries.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

If a mds has stopped, close its session and clean up its session
requests/caps. The process is similar to handling SESSION_CLOSE
initiated by mds.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

__unregister_session() free the session if it drops the last
reference. We should grab an extra reference if we want to use
session after __unregister_session().
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

mdsmap::m_max_mds is the expected count of active mds. It's not the
max rank of active mds. User can decrease mdsmap::m_max_mds, but does
not stop mds whose rank >= mdsmap::m_max_mds.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Add a readonly, exported to sysfs module parameter so that userspace
can generate meaningful error messages.  It's a bit funky, but there is
no other libceph-specific place.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

No reason to hide CephFS-specific features in the rbd case.  Recent
feature bits mix RADOS and CephFS-specific stuff together anyway.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Pull x86 fixes from Thomas Gleixner:
 "The final fixes for 4.11:

   - prevent a triple fault with function graph tracing triggered via
     suspend to ram

   - prevent optimizing for size when function graph tracing is enabled
     and the compiler does not support -mfentry

   - prevent mwaitx() being called with a zero timeout as mwaitx() might
     never return. Observed on the new Ryzen CPUs"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Prevent timer value 0 for MWAITX
  x86/build: convert function graph '-Os' error to warning
  ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram

Pull scheduler fix from Thomas Gleixner:
 "A single fix for a cputime accounting regression which got introduced
  in the 4.11 cycle"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Fix ksoftirqd cputime accounting regression

Newer hardware has uncovered a bug in the software implementation of
using MWAITX for the delay function. A value of 0 for the timer is meant
to indicate that a timeout will not be used to exit MWAITX. On newer
hardware this can result in MWAITX never returning, resulting in NMI
soft lockup messages being printed. On older hardware, some of the other
conditions under which MWAITX can exit masked this issue. The AMD APM
does not currently document this and will be updated.

Please refer to http://marc.info/?l=kvm&m=148950623231140 for
information regarding NMI soft lockup messages on an AMD Ryzen 1800X.
This has been root-caused as a 0 passed to MWAITX causing it to wait
indefinitely.

This change has the added benefit of avoiding the unnecessary setup of
MONITORX/MWAITX when the delay value is zero.
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Link: http://lkml.kernel.org/r/1493156643-29366-1-git-send-email-Janakarajan.Natarajan@amd.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

Pull iov iter fix from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix a braino in ITER_PIPE iov_iter_revert()

Fixes: 27c0e374Tested-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull clk fix from Stephen Boyd:
 "One odd config build fix for a recent Allwinner clock driver change
  that got merged. The common code called code in another file that
  wasn't always built. This just forces it on so people don't run into
  this bad configuration"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: sunxi-ng: always select CCU_GATE

Pull networking fixes from David Miller:
 "Just a couple more stragglers, I really hope this is it.

  1) Don't let frags slip down into the GRO segmentation handlers, from
     Steffen Klassert.

  2) Truesize under-estimation triggers warnings in TCP over loopback
     with socket filters, 2 part fix from Eric Dumazet.

  3) Fix undesirable reset of bonding MTU to ETH_HLEN on slave removal,
     from Paolo Abeni.

  4) If we flush the XFRM policy after garbage collection, it doesn't
     work because stray entries can be created afterwards. Fix from Xin
     Long.

  5) Hung socket connection fixes in TIPC from Parthasarathy Bhuvaragan.

  6) Fix GRO regression with IPSEC when netfilter is disabled, from
     Sabrina Dubroca.

  7) Fix cpsw driver Kconfig dependency regression, from Arnd Bergmann"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: hso: register netdev later to avoid a race condition
  net: adjust skb->truesize in ___pskb_trim()
  tcp: do not underestimate skb->truesize in tcp_trim_head()
  bonding: avoid defaulting hard_header_len to ETH_HLEN on slave removal
  ipv4: Don't pass IP fragments to upper layer GRO handlers.
  cpsw/netcp: refine cpts dependency
  tipc: close the connection if protocol messages contain errors
  tipc: improve error validations for sockets in CONNECTING state
  tipc: Fix missing connection request handling
  xfrm: fix GRO for !CONFIG_NETFILTER
  xfrm: do the garbage collection after flushing policy

If the netdev is accessed before the urbs are initialized,
there will be NULL pointer dereferences. That is avoided by
registering it when it is fully initialized.

This case occurs e.g. if dhcpcd is running in the background
and the device is probed, either after insmod hso or
when the device appears on the usb bus.

A backtrace is the following:

[ 1357.356048] usb 1-2: new high-speed USB device number 12 using ehci-omap
[ 1357.551177] usb 1-2: New USB device found, idVendor=0af0, idProduct=8800
[ 1357.558654] usb 1-2: New USB device strings: Mfr=3, Product=2, SerialNumber=0
[ 1357.568572] usb 1-2: Product: Globetrotter HSUPA Modem
[ 1357.574096] usb 1-2: Manufacturer: Option N.V.
[ 1357.685882] hso 1-2:1.5: Not our interface
[ 1460.886352] hso: unloaded
[ 1460.889984] usbcore: deregistering interface driver hso
[ 1513.769134] hso: ../drivers/net/usb/hso.c: Option Wireless
[ 1513.846771] Unable to handle kernel NULL pointer dereference at virtual address 00000030
[ 1513.887664] hso 1-2:1.5: Not our interface
[ 1513.906890] usbcore: registered new interface driver hso
[ 1513.937988] pgd = ecdec000
[ 1513.949890] [00000030] *pgd=acd15831, *pte=00000000, *ppte=00000000
[ 1513.956573] Internal error: Oops: 817 [#1] PREEMPT SMP ARM
[ 1513.962371] Modules linked in: hso usb_f_ecm omap2430 bnep bluetooth g_ether usb_f_rndis u_ether libcomposite configfs ipv6 arc4 wl18xx wlcore mac80211 cfg80211 bq27xxx_battery panel_tpo_td028ttec1 omapdrm drm_kms_helper cfbfillrect snd_soc_simple_card syscopyarea cfbimgblt snd_soc_simple_card_utils sysfillrect sysimgblt fb_sys_fops snd_soc_omap_twl4030 cfbcopyarea encoder_opa362 drm twl4030_madc_hwmon wwan_on_off snd_soc_gtm601 pwm_omap_dmtimer generic_adc_battery connector_analog_tv pwm_bl extcon_gpio omap3_isp wlcore_sdio videobuf2_dma_contig videobuf2_memops w1_bq27000 videobuf2_v4l2 videobuf2_core omap_hdq snd_soc_omap_mcbsp ov9650 snd_soc_omap bmp280_i2c bmg160_i2c v4l2_common snd_pcm_dmaengine bmp280 bmg160_core at24 bmc150_magn_i2c nvmem_core videodev phy_twl4030_usb bmc150_accel_i2c tsc2007
[ 1514.037384]  bmc150_magn bmc150_accel_core media leds_tca6507 bno055 industrialio_triggered_buffer kfifo_buf gpio_twl4030 musb_hdrc snd_soc_twl4030 twl4030_vibra twl4030_madc twl4030_pwrbutton twl4030_charger industrialio w2sg0004 ehci_omap omapdss [last unloaded: hso]
[ 1514.062622] CPU: 0 PID: 3433 Comm: dhcpcd Tainted: G        W       4.11.0-rc8-letux+ #1
[ 1514.071136] Hardware name: Generic OMAP36xx (Flattened Device Tree)
[ 1514.077758] task: ee748240 task.stack: ecdd6000
[ 1514.082580] PC is at hso_start_net_device+0x50/0xc0 [hso]
[ 1514.088287] LR is at hso_net_open+0x68/0x84 [hso]
[ 1514.093231] pc : [<bf79c304>]    lr : [<bf79ced8>]    psr: a00f0013
sp : ecdd7e20  ip : 00000000  fp : ffffffff
[ 1514.105316] r10: 00000000  r9 : ed0e080c  r8 : ecd8fe2c
[ 1514.110839] r7 : bf79cef4  r6 : ecd8fe00  r5 : 00000000  r4 : ed0dbd80
[ 1514.117706] r3 : 00000000  r2 : c0020c80  r1 : 00000000  r0 : ecdb7800
[ 1514.124572] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[ 1514.132110] Control: 10c5387d  Table: acdec019  DAC: 00000051
[ 1514.138153] Process dhcpcd (pid: 3433, stack limit = 0xecdd6218)
[ 1514.144470] Stack: (0xecdd7e20 to 0xecdd8000)
[ 1514.149078] 7e20: ed0dbd80 ecd8fe98 00000001 00000000 ecd8f800 ecd8fe00 ecd8fe60 00000000
[ 1514.157714] 7e40: ed0e080c bf79ced8 bf79ce70 ecd8f800 00000001 bf7a0258 ecd8f830 c068d958
[ 1514.166320] 7e60: c068d8b8 ecd8f800 00000001 00001091 00001090 c068dba4 ecd8f800 00001090
[ 1514.174926] 7e80: ecd8f940 ecd8f800 00000000 c068dc60 00000000 00000001 ed0e0800 ecd8f800
[ 1514.183563] 7ea0: 00000000 c06feaa8 c0ca39c2 beea57dc 00000020 00000000 306f7368 00000000
[ 1514.192169] 7ec0: 00000000 00000000 00001091 00000000 00000000 00000000 00000000 00008914
[ 1514.200805] 7ee0: eaa9ab60 beea57dc c0c9bfc0 eaa9ab40 00000006 00000000 00046858 c066a948
[ 1514.209411] 7f00: beea57dc eaa9ab60 ecc6b0c0 c02837b0 00000006 c0282c90 0000c000 c0283654
[ 1514.218017] 7f20: c09b0c00 c098bc31 00000001 c0c5e513 c0c5e513 00000000 c0151354 c01a20c0
[ 1514.226654] 7f40: c0c5e513 c01a3134 ecdd6000 c01a3160 ee7487f0 600f0013 00000000 ee748240
[ 1514.235260] 7f60: ee748734 00000000 ecc6b0c0 ecc6b0c0 beea57dc 00008914 00000006 00000000
[ 1514.243896] 7f80: 00046858 c02837b0 00001091 0003a1f0 00046608 0003a248 00000036 c01071e4
[ 1514.252502] 7fa0: ecdd6000 c0107040 0003a1f0 00046608 00000006 00008914 beea57dc 00001091
[ 1514.261108] 7fc0: 0003a1f0 00046608 0003a248 00000036 0003ac0c 00046608 00046610 00046858
[ 1514.269744] 7fe0: 0003a0ac beea57d4 000167eb b6f23106 400f0030 00000006 00000000 00000000
[ 1514.278411] [<bf79c304>] (hso_start_net_device [hso]) from [<bf79ced8>] (hso_net_open+0x68/0x84 [hso])
[ 1514.288238] [<bf79ced8>] (hso_net_open [hso]) from [<c068d958>] (__dev_open+0xa0/0xf4)
[ 1514.296600] [<c068d958>] (__dev_open) from [<c068dba4>] (__dev_change_flags+0x8c/0x130)
[ 1514.305023] [<c068dba4>] (__dev_change_flags) from [<c068dc60>] (dev_change_flags+0x18/0x48)
[ 1514.313934] [<c068dc60>] (dev_change_flags) from [<c06feaa8>] (devinet_ioctl+0x348/0x714)
[ 1514.322540] [<c06feaa8>] (devinet_ioctl) from [<c066a948>] (sock_ioctl+0x2b0/0x308)
[ 1514.330627] [<c066a948>] (sock_ioctl) from [<c0282c90>] (vfs_ioctl+0x20/0x34)
[ 1514.338165] [<c0282c90>] (vfs_ioctl) from [<c0283654>] (do_vfs_ioctl+0x82c/0x93c)
[ 1514.346038] [<c0283654>] (do_vfs_ioctl) from [<c02837b0>] (SyS_ioctl+0x4c/0x74)
[ 1514.353759] [<c02837b0>] (SyS_ioctl) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
[ 1514.361755] Code: e3822103 e3822080 e1822781 e5981014 (e5832030)
[ 1514.510833] ---[ end trace dfb3e53c657f34a0 ]---
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Andrey found a way to trigger the WARN_ON_ONCE(delta < len) in
skb_try_coalesce() using syzkaller and a filter attached to a TCP
socket.

As we did recently in commit 158f323b ("net: adjust skb->truesize in
pskb_expand_head()") we can adjust skb->truesize from ___pskb_trim(),
via a call to skb_condense().

If all frags were freed, then skb->truesize can be recomputed.

This call can be done if skb is not yet owned, or destructor is
sock_edemux().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Andrey found a way to trigger the WARN_ON_ONCE(delta < len) in
skb_try_coalesce() using syzkaller and a filter attached to a TCP
socket over loopback interface.

I believe one issue with looped skbs is that tcp_trim_head() can end up
producing skb with under estimated truesize.

It hardly matters for normal conditions, since packets sent over
loopback are never truncated.

Bytes trimmed from skb->head should not change skb truesize, since
skb->head is not reallocated.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>