1. 27 Apr, 2019 5 commits
  2. 26 Apr, 2019 23 commits
  3. 25 Apr, 2019 8 commits
    • Xie XiuQi's avatar
      sched/numa: Fix a possible divide-by-zero · a860fa7b
      Xie XiuQi authored
      sched_clock_cpu() may not be consistent between CPUs. If a task
      migrates to another CPU, then se.exec_start is set to that CPU's
      rq_clock_task() by update_stats_curr_start(). Specifically, the new
      value might be before the old value due to clock skew.
      
      So then if in numa_get_avg_runtime() the expression:
      
        'now - p->last_task_numa_placement'
      
      ends up as -1, then the divider '*period + 1' in task_numa_placement()
      is 0 and things go bang. Similar to update_curr(), check if time goes
      backwards to avoid this.
      
      [ peterz: Wrote new changelog. ]
      [ mingo: Tweaked the code comment. ]
      Signed-off-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: cj.chengjian@huawei.com
      Cc: <stable@vger.kernel.org>
      Link: http://lkml.kernel.org/r/20190425080016.GX11158@hirez.programming.kicks-ass.netSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      a860fa7b
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-5.1-rc7' of git://github.com/ceph/ceph-client · 8113a85f
      Linus Torvalds authored
      Pull ceph fixes from Ilya Dryomov:
       "dentry name handling fixes from Jeff and a memory leak fix from Zheng.
      
        Both are old issues, marked for stable"
      
      * tag 'ceph-for-5.1-rc7' of git://github.com/ceph/ceph-client:
        ceph: fix ci->i_head_snapc leak
        ceph: handle the case where a dentry has been renamed on outstanding req
        ceph: ensure d_name stability in ceph_dentry_hash()
        ceph: only use d_name directly when parent is locked
      8113a85f
    • Linus Torvalds's avatar
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · f6f3e747
      Linus Torvalds authored
      Pull crypto fixes from Herbert Xu:
       "This fixes a bug in xts and lrw where they may sleep in an atomic
        context"
      
      * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
        crypto: lrw - Fix atomic sleep when walking skcipher
        crypto: xts - Fix atomic sleep when walking skcipher
      f6f3e747
    • Nikolay Borisov's avatar
      btrfs: Switch memory allocations in async csum calculation path to kvmalloc · a3d46aea
      Nikolay Borisov authored
      Recent multi-page biovec rework allowed creation of bios that can span
      large regions - up to 128 megabytes in the case of btrfs. OTOH btrfs'
      submission path currently allocates a contiguous array to store the
      checksums for every bio submitted. This means we can request up to
      (128mb / BTRFS_SECTOR_SIZE) * 4 bytes + 32bytes of memory from kmalloc.
      On busy systems with possibly fragmented memory said kmalloc can fail
      which will trigger BUG_ON due to improper error handling IO submission
      context in btrfs.
      
      Until error handling is improved or bios in btrfs limited to a more
      manageable size (e.g. 1m) let's use kvmalloc to fallback to vmalloc for
      such large allocations. There is no hard requirement that the memory
      allocated for checksums during IO submission has to be contiguous, but
      this is a simple fix that does not require several non-contiguous
      allocations.
      
      For small writes this is unlikely to have any visible effect since
      kmalloc will still satisfy allocation requests as usual. For larger
      requests the code will just fallback to vmalloc.
      
      We've performed evaluation on several workload types and there was no
      significant difference kmalloc vs kvmalloc.
      Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      a3d46aea
    • Jonas Karlman's avatar
      drm/bridge: dw-hdmi: fix SCDC configuration for ddc-i2c-bus · c4cba44e
      Jonas Karlman authored
      When ddc-i2c-bus property is used, a NULL pointer dereference is reported:
      
      [   31.041669] Unable to handle kernel NULL pointer dereference at virtual address 00000008
      [   31.041671] pgd = 4d3c16f6
      [   31.041673] [00000008] *pgd=00000000
      [   31.041678] Internal error: Oops: 5 [#1] SMP ARM
      
      [   31.041711] Hardware name: Rockchip (Device Tree)
      [   31.041718] PC is at i2c_transfer+0x8/0xe4
      [   31.041721] LR is at drm_scdc_read+0x54/0x84
      [   31.041723] pc : [<c073273c>]    lr : [<c05926c4>]    psr: 280f0013
      [   31.041725] sp : edffdad0  ip : 5ccb5511  fp : 00000058
      [   31.041727] r10: 00000780  r9 : edf91608  r8 : c11b0f48
      [   31.041728] r7 : 00000438  r6 : 00000000  r5 : 00000000  r4 : 00000000
      [   31.041730] r3 : edffdae7  r2 : 00000002  r1 : edffdaec  r0 : 00000000
      
      [   31.041908] [<c073273c>] (i2c_transfer) from [<c05926c4>] (drm_scdc_read+0x54/0x84)
      [   31.041913] [<c05926c4>] (drm_scdc_read) from [<c0592858>] (drm_scdc_set_scrambling+0x30/0xbc)
      [   31.041919] [<c0592858>] (drm_scdc_set_scrambling) from [<c05cc0f4>] (dw_hdmi_update_power+0x1440/0x1610)
      [   31.041926] [<c05cc0f4>] (dw_hdmi_update_power) from [<c05cc574>] (dw_hdmi_bridge_enable+0x2c/0x70)
      [   31.041932] [<c05cc574>] (dw_hdmi_bridge_enable) from [<c05aed48>] (drm_bridge_enable+0x24/0x34)
      [   31.041938] [<c05aed48>] (drm_bridge_enable) from [<c0591060>] (drm_atomic_helper_commit_modeset_enables+0x114/0x220)
      [   31.041943] [<c0591060>] (drm_atomic_helper_commit_modeset_enables) from [<c05c3fe0>] (rockchip_atomic_helper_commit_tail_rpm+0x28/0x64)
      
      hdmi->i2c may not be set when ddc-i2c-bus property is used in device tree.
      Fix this by using hdmi->ddc as the i2c adapter when calling drm_scdc_*().
      Also report that SCDC is not supported when there is no DDC bus.
      
      Fixes: 264fce6c ("drm/bridge: dw-hdmi: Add SCDC and TMDS Scrambling support")
      Signed-off-by: default avatarJonas Karlman <jonas@kwiboo.se>
      Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
      Reviewed-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
      Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
      Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/VE1PR03MB59031814B5BCAB2152923BDAAC210@VE1PR03MB5903.eurprd03.prod.outlook.com
      c4cba44e
    • Geert Uytterhoeven's avatar
      gpio: Fix gpiochip_add_data_with_key() error path · 35779890
      Geert Uytterhoeven authored
      The err_remove_chip block is too coarse, and may perform cleanup that
      must not be done.  E.g. if of_gpiochip_add() fails, of_gpiochip_remove()
      is still called, causing:
      
          OF: ERROR: Bad of_node_put() on /soc/gpio@e6050000
          CPU: 1 PID: 20 Comm: kworker/1:1 Not tainted 5.1.0-rc2-koelsch+ #407
          Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
          Workqueue: events deferred_probe_work_func
          [<c020ec74>] (unwind_backtrace) from [<c020ae58>] (show_stack+0x10/0x14)
          [<c020ae58>] (show_stack) from [<c07c1224>] (dump_stack+0x7c/0x9c)
          [<c07c1224>] (dump_stack) from [<c07c5a80>] (kobject_put+0x94/0xbc)
          [<c07c5a80>] (kobject_put) from [<c0470420>] (gpiochip_add_data_with_key+0x8d8/0xa3c)
          [<c0470420>] (gpiochip_add_data_with_key) from [<c0473738>] (gpio_rcar_probe+0x1d4/0x314)
          [<c0473738>] (gpio_rcar_probe) from [<c052fca8>] (platform_drv_probe+0x48/0x94)
      
      and later, if a GPIO consumer tries to use a GPIO from a failed
      controller:
      
          WARNING: CPU: 0 PID: 1 at lib/refcount.c:156 kobject_get+0x38/0x4c
          refcount_t: increment on 0; use-after-free.
          Modules linked in:
          CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.1.0-rc2-koelsch+ #407
          Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
          [<c020ec74>] (unwind_backtrace) from [<c020ae58>] (show_stack+0x10/0x14)
          [<c020ae58>] (show_stack) from [<c07c1224>] (dump_stack+0x7c/0x9c)
          [<c07c1224>] (dump_stack) from [<c0221580>] (__warn+0xd0/0xec)
          [<c0221580>] (__warn) from [<c02215e0>] (warn_slowpath_fmt+0x44/0x6c)
          [<c02215e0>] (warn_slowpath_fmt) from [<c07c58fc>] (kobject_get+0x38/0x4c)
          [<c07c58fc>] (kobject_get) from [<c068b3ec>] (of_node_get+0x14/0x1c)
          [<c068b3ec>] (of_node_get) from [<c0686f24>] (of_find_node_by_phandle+0xc0/0xf0)
          [<c0686f24>] (of_find_node_by_phandle) from [<c0686fbc>] (of_phandle_iterator_next+0x68/0x154)
          [<c0686fbc>] (of_phandle_iterator_next) from [<c0687fe4>] (__of_parse_phandle_with_args+0x40/0xd0)
          [<c0687fe4>] (__of_parse_phandle_with_args) from [<c0688204>] (of_parse_phandle_with_args_map+0x100/0x3ac)
          [<c0688204>] (of_parse_phandle_with_args_map) from [<c0471240>] (of_get_named_gpiod_flags+0x38/0x380)
          [<c0471240>] (of_get_named_gpiod_flags) from [<c046f864>] (gpiod_get_from_of_node+0x24/0xd8)
          [<c046f864>] (gpiod_get_from_of_node) from [<c0470aa4>] (devm_fwnode_get_index_gpiod_from_child+0xa0/0x144)
          [<c0470aa4>] (devm_fwnode_get_index_gpiod_from_child) from [<c05f425c>] (gpio_keys_probe+0x418/0x7bc)
          [<c05f425c>] (gpio_keys_probe) from [<c052fca8>] (platform_drv_probe+0x48/0x94)
      
      Fix this by splitting the cleanup block, and adding a missing call to
      gpiochip_irqchip_remove().
      
      Fixes: 28355f81 ("gpio: defer probe if pinctrl cannot be found")
      Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
      Reviewed-by: default avatarMukesh Ojha <mojha@codeaurora.org>
      Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      35779890
    • Thomas Hellstrom's avatar
      drm/vmwgfx: Fix dma API layer violation · 81103355
      Thomas Hellstrom authored
      Remove the check for IOMMU presence since it was considered a
      layer violation.
      This means we have no reliable way to destinguish between coherent
      hardware IOMMU DMA address translations and incoherent SWIOTLB DMA
      address translations, which we can't handle. So always presume the
      former. This means that if anybody forces SWIOTLB without also setting
      the vmw_force_coherent=1 vmwgfx option, driver operation will fail,
      like it will on most other graphics drivers.
      Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      81103355
    • Harry Pan's avatar
      perf/x86/intel: Update KBL Package C-state events to also include PC8/PC9/PC10 counters · 82c99f7a
      Harry Pan authored
      Kaby Lake (and Coffee Lake) has PC8/PC9/PC10 residency counters.
      
      This patch updates the list of Kaby/Coffee Lake PMU event counters
      from the snb_cstates[] list of events to the hswult_cstates[]
      list of events, which keeps all previously supported events and
      also adds the PKG_C8, PKG_C9 and PKG_C10 residency counters.
      
      This allows user space tools to profile them through the perf interface.
      Signed-off-by: default avatarHarry Pan <harry.pan@intel.com>
      Cc: <stable@vger.kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vince Weaver <vincent.weaver@maine.edu>
      Cc: gs0622@gmail.com
      Link: http://lkml.kernel.org/r/20190424145033.1924-1-harry.pan@intel.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      82c99f7a
  4. 24 Apr, 2019 4 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · cd8dead0
      Linus Torvalds authored
      Pull networking fixes from David Miller:
       "Just the usual assortment of small'ish fixes:
      
         1) Conntrack timeout is sometimes not initialized properly, from
            Alexander Potapenko.
      
         2) Add a reasonable range limit to tcp_min_rtt_wlen to avoid
            undefined behavior. From ZhangXiaoxu.
      
         3) des1 field of descriptor in stmmac driver is initialized with the
            wrong variable. From Yue Haibing.
      
         4) Increase mlxsw pci sw reset timeout a little bit more, from Ido
            Schimmel.
      
         5) Match IOT2000 stmmac devices more accurately, from Su Bao Cheng.
      
         6) Fallback refcount fix in TLS code, from Jakub Kicinski.
      
         7) Fix max MTU check when using XDP in mlx5, from Maxim Mikityanskiy.
      
         8) Fix recursive locking in team driver, from Hangbin Liu.
      
         9) Fix tls_set_device_offload_Rx() deadlock, from Jakub Kicinski.
      
        10) Don't use napi_alloc_frag() outside of softiq context of socionext
            driver, from Ilias Apalodimas.
      
        11) MAC address increment overflow in ncsi, from Tao Ren.
      
        12) Fix a regression in 8K/1M pool switching of RDS, from Zhu Yanjun.
      
        13) ipv4_link_failure has to validate the headers that are actually
            there because RAW sockets can pass in arbitrary garbage, from Eric
            Dumazet"
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (43 commits)
        ipv4: add sanity checks in ipv4_link_failure()
        net/rose: fix unbound loop in rose_loopback_timer()
        rxrpc: fix race condition in rxrpc_input_packet()
        net: rds: exchange of 8K and 1M pool
        net: vrf: Fix operation not supported when set vrf mac
        net/ncsi: handle overflow when incrementing mac address
        net: socionext: replace napi_alloc_frag with the netdev variant on init
        net: atheros: fix spelling mistake "underun" -> "underrun"
        spi: ST ST95HF NFC: declare missing of table
        spi: Micrel eth switch: declare missing of table
        net: stmmac: move stmmac_check_ether_addr() to driver probe
        netfilter: fix nf_l4proto_log_invalid to log invalid packets
        netfilter: never get/set skb->tstamp
        netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON
        Documentation: decnet: remove reference to CONFIG_DECNET_ROUTE_FWMARK
        dt-bindings: add an explanation for internal phy-mode
        net/tls: don't leak IV and record seq when offload fails
        net/tls: avoid potential deadlock in tls_set_device_offload_rx()
        selftests/net: correct the return value for run_afpackettests
        team: fix possible recursive locking when add slaves
        ...
      cd8dead0
    • Linus Torvalds's avatar
      Merge tag 'leds-for-5.1-rc7' of... · 11bfe647
      Linus Torvalds authored
      Merge tag 'leds-for-5.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds
      
      Pull LED update from Jacek Anaszewski:
       "A single change to MAINTAINERS:
      
        We announce a new LED reviewer - Dan Murphy"
      
      * tag 'leds-for-5.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
        MAINTAINERS: LEDs: Add designated reviewer for LED subsystem
      11bfe647
    • Eric Dumazet's avatar
      ipv4: add sanity checks in ipv4_link_failure() · 20ff83f1
      Eric Dumazet authored
      Before calling __ip_options_compile(), we need to ensure the network
      header is a an IPv4 one, and that it is already pulled in skb->head.
      
      RAW sockets going through a tunnel can end up calling ipv4_link_failure()
      with total garbage in the skb, or arbitrary lengthes.
      
      syzbot report :
      
      BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:355 [inline]
      BUG: KASAN: stack-out-of-bounds in __ip_options_echo+0x294/0x1120 net/ipv4/ip_options.c:123
      Write of size 69 at addr ffff888096abf068 by task syz-executor.4/9204
      
      CPU: 0 PID: 9204 Comm: syz-executor.4 Not tainted 5.1.0-rc5+ #77
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:77 [inline]
       dump_stack+0x172/0x1f0 lib/dump_stack.c:113
       print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
       kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
       check_memory_region_inline mm/kasan/generic.c:185 [inline]
       check_memory_region+0x123/0x190 mm/kasan/generic.c:191
       memcpy+0x38/0x50 mm/kasan/common.c:133
       memcpy include/linux/string.h:355 [inline]
       __ip_options_echo+0x294/0x1120 net/ipv4/ip_options.c:123
       __icmp_send+0x725/0x1400 net/ipv4/icmp.c:695
       ipv4_link_failure+0x29f/0x550 net/ipv4/route.c:1204
       dst_link_failure include/net/dst.h:427 [inline]
       vti6_xmit net/ipv6/ip6_vti.c:514 [inline]
       vti6_tnl_xmit+0x10d4/0x1c0c net/ipv6/ip6_vti.c:553
       __netdev_start_xmit include/linux/netdevice.h:4414 [inline]
       netdev_start_xmit include/linux/netdevice.h:4423 [inline]
       xmit_one net/core/dev.c:3292 [inline]
       dev_hard_start_xmit+0x1b2/0x980 net/core/dev.c:3308
       __dev_queue_xmit+0x271d/0x3060 net/core/dev.c:3878
       dev_queue_xmit+0x18/0x20 net/core/dev.c:3911
       neigh_direct_output+0x16/0x20 net/core/neighbour.c:1527
       neigh_output include/net/neighbour.h:508 [inline]
       ip_finish_output2+0x949/0x1740 net/ipv4/ip_output.c:229
       ip_finish_output+0x73c/0xd50 net/ipv4/ip_output.c:317
       NF_HOOK_COND include/linux/netfilter.h:278 [inline]
       ip_output+0x21f/0x670 net/ipv4/ip_output.c:405
       dst_output include/net/dst.h:444 [inline]
       NF_HOOK include/linux/netfilter.h:289 [inline]
       raw_send_hdrinc net/ipv4/raw.c:432 [inline]
       raw_sendmsg+0x1d2b/0x2f20 net/ipv4/raw.c:663
       inet_sendmsg+0x147/0x5d0 net/ipv4/af_inet.c:798
       sock_sendmsg_nosec net/socket.c:651 [inline]
       sock_sendmsg+0xdd/0x130 net/socket.c:661
       sock_write_iter+0x27c/0x3e0 net/socket.c:988
       call_write_iter include/linux/fs.h:1866 [inline]
       new_sync_write+0x4c7/0x760 fs/read_write.c:474
       __vfs_write+0xe4/0x110 fs/read_write.c:487
       vfs_write+0x20c/0x580 fs/read_write.c:549
       ksys_write+0x14f/0x2d0 fs/read_write.c:599
       __do_sys_write fs/read_write.c:611 [inline]
       __se_sys_write fs/read_write.c:608 [inline]
       __x64_sys_write+0x73/0xb0 fs/read_write.c:608
       do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
      RIP: 0033:0x458c29
      Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
      RSP: 002b:00007f293b44bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
      RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29
      RDX: 0000000000000014 RSI: 00000000200002c0 RDI: 0000000000000003
      RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000246 R12: 00007f293b44c6d4
      R13: 00000000004c8623 R14: 00000000004ded68 R15: 00000000ffffffff
      
      The buggy address belongs to the page:
      page:ffffea00025aafc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
      flags: 0x1fffc0000000000()
      raw: 01fffc0000000000 0000000000000000 ffffffff025a0101 0000000000000000
      raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
      page dumped because: kasan: bad access detected
      
      Memory state around the buggy address:
       ffff888096abef80: 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 f2
       ffff888096abf000: f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00
      >ffff888096abf080: 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00
                               ^
       ffff888096abf100: 00 00 00 00 f1 f1 f1 f1 00 00 f3 f3 00 00 00 00
       ffff888096abf180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
      
      Fixes: ed0de45a ("ipv4: recompile ip options in ipv4_link_failure")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Stephen Suryaputra <ssuryaextr@gmail.com>
      Acked-by: default avatarWillem de Bruijn <willemb@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      20ff83f1
    • Eric Dumazet's avatar
      net/rose: fix unbound loop in rose_loopback_timer() · 0453c682
      Eric Dumazet authored
      This patch adds a limit on the number of skbs that fuzzers can queue
      into loopback_queue. 1000 packets for rose loopback seems more than enough.
      
      Then, since we now have multiple cpus in most linux hosts,
      we also need to limit the number of skbs rose_loopback_timer()
      can dequeue at each round.
      
      rose_loopback_queue() can be drop-monitor friendly, calling
      consume_skb() or kfree_skb() appropriately.
      
      Finally, use mod_timer() instead of del_timer() + add_timer()
      
      syzbot report was :
      
      rcu: INFO: rcu_preempt self-detected stall on CPU
      rcu:    0-...!: (10499 ticks this GP) idle=536/1/0x4000000000000002 softirq=103291/103291 fqs=34
      rcu:     (t=10500 jiffies g=140321 q=323)
      rcu: rcu_preempt kthread starved for 10426 jiffies! g140321 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
      rcu: RCU grace-period kthread stack dump:
      rcu_preempt     I29168    10      2 0x80000000
      Call Trace:
       context_switch kernel/sched/core.c:2877 [inline]
       __schedule+0x813/0x1cc0 kernel/sched/core.c:3518
       schedule+0x92/0x180 kernel/sched/core.c:3562
       schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803
       rcu_gp_fqs_loop kernel/rcu/tree.c:1971 [inline]
       rcu_gp_kthread+0x962/0x17b0 kernel/rcu/tree.c:2128
       kthread+0x357/0x430 kernel/kthread.c:253
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
      NMI backtrace for cpu 0
      CPU: 0 PID: 7632 Comm: kworker/0:4 Not tainted 5.1.0-rc5+ #172
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Workqueue: events iterate_cleanup_work
      Call Trace:
       <IRQ>
       __dump_stack lib/dump_stack.c:77 [inline]
       dump_stack+0x172/0x1f0 lib/dump_stack.c:113
       nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
       nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
       arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
       trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
       rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1223
       print_cpu_stall kernel/rcu/tree.c:1360 [inline]
       check_cpu_stall kernel/rcu/tree.c:1434 [inline]
       rcu_pending kernel/rcu/tree.c:3103 [inline]
       rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
       update_process_times+0x32/0x80 kernel/time/timer.c:1635
       tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
       tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
       __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
       __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
       hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
       local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
       smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
       apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
      RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:95
      Code: 89 25 b4 6e ec 08 41 bc f4 ff ff ff e8 cd 5d ea ff 48 c7 05 9e 6e ec 08 00 00 00 00 e9 a4 e9 ff ff 90 90 90 90 90 90 90 90 90 <55> 48 89 e5 48 8b 75 08 65 48 8b 04 25 00 ee 01 00 65 8b 15 c8 60
      RSP: 0018:ffff8880ae807ce0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
      RAX: ffff88806fd40640 RBX: dffffc0000000000 RCX: ffffffff863fbc56
      RDX: 0000000000000100 RSI: ffffffff863fbc1d RDI: ffff88808cf94228
      RBP: ffff8880ae807d10 R08: ffff88806fd40640 R09: ffffed1015d00f8b
      R10: ffffed1015d00f8a R11: 0000000000000003 R12: ffff88808cf941c0
      R13: 00000000fffff034 R14: ffff8882166cd840 R15: 0000000000000000
       rose_loopback_timer+0x30d/0x3f0 net/rose/rose_loopback.c:91
       call_timer_fn+0x190/0x720 kernel/time/timer.c:1325
       expire_timers kernel/time/timer.c:1362 [inline]
       __run_timers kernel/time/timer.c:1681 [inline]
       __run_timers kernel/time/timer.c:1649 [inline]
       run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694
       __do_softirq+0x266/0x95a kernel/softirq.c:293
       do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1027
      
      Fixes: 1da177e4 ("Linux-2.6.12-rc2")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0453c682