Re: [PATCH] netdevsim: init u64 stats for 32bit hardware
From: Dmitry Vyukov <dvyukov@google.com>
Date: 2021-01-28 07:27:25
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On Thu, Jan 28, 2021 at 3:43 AM Hillf Danton [off-list ref] wrote:
Init the u64 stats in order to avoid the lockdep prints on the 32bit hardware like
FTR this is not just to avoid lockdep prints, but also to prevent very real stalls in production. u64_stats_init initializes seqlock, if the uninitialized selock->sequence would be odd, the kernel will stall. Maintainers, please send this upstream on your earliest convenience, this breaks all 32-bit arches for testing purposes. Thanks
quoted hunk
INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 0 PID: 4695 Comm: syz-executor.0 Not tainted 5.11.0-rc5-syzkaller #0 Hardware name: ARM-Versatile Express Backtrace: [<826fc5b8>] (dump_backtrace) from [<826fc82c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252) [<826fc814>] (show_stack) from [<8270d1f8>] (__dump_stack lib/dump_stack.c:79 [inline]) [<826fc814>] (show_stack) from [<8270d1f8>] (dump_stack+0xa8/0xc8 lib/dump_stack.c:120) [<8270d150>] (dump_stack) from [<802bf9c0>] (assign_lock_key kernel/locking/lockdep.c:935 [inline]) [<8270d150>] (dump_stack) from [<802bf9c0>] (register_lock_class+0xabc/0xb68 kernel/locking/lockdep.c:1247) [<802bef04>] (register_lock_class) from [<802baa2c>] (__lock_acquire+0x84/0x32d4 kernel/locking/lockdep.c:4711) [<802ba9a8>] (__lock_acquire) from [<802be840>] (lock_acquire.part.0+0xf0/0x554 kernel/locking/lockdep.c:5442) [<802be750>] (lock_acquire.part.0) from [<802bed10>] (lock_acquire+0x6c/0x74 kernel/locking/lockdep.c:5415) [<802beca4>] (lock_acquire) from [<81560548>] (seqcount_lockdep_reader_access include/linux/seqlock.h:103 [inline]) [<802beca4>] (lock_acquire) from [<81560548>] (__u64_stats_fetch_begin include/linux/u64_stats_sync.h:164 [inline]) [<802beca4>] (lock_acquire) from [<81560548>] (u64_stats_fetch_begin include/linux/u64_stats_sync.h:175 [inline]) [<802beca4>] (lock_acquire) from [<81560548>] (nsim_get_stats64+0xdc/0xf0 drivers/net/netdevsim/netdev.c:70) [<8156046c>] (nsim_get_stats64) from [<81e2efa0>] (dev_get_stats+0x44/0xd0 net/core/dev.c:10405) [<81e2ef5c>] (dev_get_stats) from [<81e53204>] (rtnl_fill_stats+0x38/0x120 net/core/rtnetlink.c:1211) [<81e531cc>] (rtnl_fill_stats) from [<81e59d58>] (rtnl_fill_ifinfo+0x6d4/0x148c net/core/rtnetlink.c:1783) [<81e59684>] (rtnl_fill_ifinfo) from [<81e5ceb4>] (rtmsg_ifinfo_build_skb+0x9c/0x108 net/core/rtnetlink.c:3798) [<81e5ce18>] (rtmsg_ifinfo_build_skb) from [<81e5d0ac>] (rtmsg_ifinfo_event net/core/rtnetlink.c:3830 [inline]) [<81e5ce18>] (rtmsg_ifinfo_build_skb) from [<81e5d0ac>] (rtmsg_ifinfo_event net/core/rtnetlink.c:3821 [inline]) [<81e5ce18>] (rtmsg_ifinfo_build_skb) from [<81e5d0ac>] (rtmsg_ifinfo+0x44/0x70 net/core/rtnetlink.c:3839) [<81e5d068>] (rtmsg_ifinfo) from [<81e45c2c>] (register_netdevice+0x664/0x68c net/core/dev.c:10103) [<81e455c8>] (register_netdevice) from [<815608bc>] (nsim_create+0xf8/0x124 drivers/net/netdevsim/netdev.c:317) [<815607c4>] (nsim_create) from [<81561184>] (__nsim_dev_port_add+0x108/0x188 drivers/net/netdevsim/dev.c:941) [<8156107c>] (__nsim_dev_port_add) from [<815620d8>] (nsim_dev_port_add_all drivers/net/netdevsim/dev.c:990 [inline]) [<8156107c>] (__nsim_dev_port_add) from [<815620d8>] (nsim_dev_probe+0x5cc/0x750 drivers/net/netdevsim/dev.c:1119) [<81561b0c>] (nsim_dev_probe) from [<815661dc>] (nsim_bus_probe+0x10/0x14 drivers/net/netdevsim/bus.c:287) [<815661cc>] (nsim_bus_probe) from [<811724c0>] (really_probe+0x100/0x50c drivers/base/dd.c:554) [<811723c0>] (really_probe) from [<811729c4>] (driver_probe_device+0xf8/0x1c8 drivers/base/dd.c:740) [<811728cc>] (driver_probe_device) from [<81172fe4>] (__device_attach_driver+0x8c/0xf0 drivers/base/dd.c:846) [<81172f58>] (__device_attach_driver) from [<8116fee0>] (bus_for_each_drv+0x88/0xd8 drivers/base/bus.c:431) [<8116fe58>] (bus_for_each_drv) from [<81172c6c>] (__device_attach+0xdc/0x1d0 drivers/base/dd.c:914) [<81172b90>] (__device_attach) from [<8117305c>] (device_initial_probe+0x14/0x18 drivers/base/dd.c:961) [<81173048>] (device_initial_probe) from [<81171358>] (bus_probe_device+0x90/0x98 drivers/base/bus.c:491) [<811712c8>] (bus_probe_device) from [<8116e77c>] (device_add+0x320/0x824 drivers/base/core.c:3109) [<8116e45c>] (device_add) from [<8116ec9c>] (device_register+0x1c/0x20 drivers/base/core.c:3182) [<8116ec80>] (device_register) from [<81566710>] (nsim_bus_dev_new drivers/net/netdevsim/bus.c:336 [inline]) [<8116ec80>] (device_register) from [<81566710>] (new_device_store+0x178/0x208 drivers/net/netdevsim/bus.c:215) [<81566598>] (new_device_store) from [<8116fcb4>] (bus_attr_store+0x2c/0x38 drivers/base/bus.c:122) [<8116fc88>] (bus_attr_store) from [<805b4b8c>] (sysfs_kf_write+0x48/0x54 fs/sysfs/file.c:139) [<805b4b44>] (sysfs_kf_write) from [<805b3c90>] (kernfs_fop_write_iter+0x128/0x1ec fs/kernfs/file.c:296) [<805b3b68>] (kernfs_fop_write_iter) from [<804d22fc>] (call_write_iter include/linux/fs.h:1901 [inline]) [<805b3b68>] (kernfs_fop_write_iter) from [<804d22fc>] (new_sync_write fs/read_write.c:518 [inline]) [<805b3b68>] (kernfs_fop_write_iter) from [<804d22fc>] (vfs_write+0x3dc/0x57c fs/read_write.c:605) [<804d1f20>] (vfs_write) from [<804d2604>] (ksys_write+0x68/0xec fs/read_write.c:658) [<804d259c>] (ksys_write) from [<804d2698>] (__do_sys_write fs/read_write.c:670 [inline]) [<804d259c>] (ksys_write) from [<804d2698>] (sys_write+0x10/0x14 fs/read_write.c:667) [<804d2688>] (sys_write) from [<80200060>] (ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64) Fixes: 83c9e13aa39a ("netdevsim: add software driver for testing offloads") Reported-by: syzbot+e74a6857f2d0efe3ad81@syzkaller.appspotmail.com Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: Jakub Kicinski <redacted> Cc: Simon Horman <redacted> Cc: Quentin Monnet <redacted> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Hillf Danton <redacted> ------ a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c@@ -296,6 +296,7 @@ nsim_create(struct nsim_dev *nsim_dev, s dev_net_set(dev, nsim_dev_net(nsim_dev)); ns = netdev_priv(dev); ns->netdev = dev; + u64_stats_init(&ns->syncp); ns->nsim_dev = nsim_dev; ns->nsim_dev_port = nsim_dev_port; ns->nsim_bus_dev = nsim_dev->nsim_bus_dev; -- --You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. 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