linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: CAI Qian <caiqian@redhat.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: tj <tj@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Chinner <david@fromorbit.com>,
	linux-xfs <linux-xfs@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>, Nick Piggin <npiggin@gmail.com>,
	linux-fsdevel@vger.kernel.org
Subject: Re: local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked)
Date: Thu, 6 Oct 2016 08:25:59 -0400 (EDT)	[thread overview]
Message-ID: <1860793605.807021.1475756759147.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <119370333.805584.1475756417736.JavaMail.zimbra@redhat.com>



----- Original Message -----
> From: "CAI Qian" <caiqian@redhat.com>
> To: "Al Viro" <viro@ZenIV.linux.org.uk>
> Cc: "tj" <tj@kernel.org>, "Linus Torvalds" <torvalds@linux-foundation.org>, "Dave Chinner" <david@fromorbit.com>,
> "linux-xfs" <linux-xfs@vger.kernel.org>, "Jens Axboe" <axboe@kernel.dk>, "Nick Piggin" <npiggin@gmail.com>,
> linux-fsdevel@vger.kernel.org
> Sent: Thursday, October 6, 2016 8:20:17 AM
> Subject: Re: local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked)
> 
> 
> 
> ----- Original Message -----
> > From: "Al Viro" <viro@ZenIV.linux.org.uk>
> > To: "CAI Qian" <caiqian@redhat.com>
> > Cc: "tj" <tj@kernel.org>, "Linus Torvalds" <torvalds@linux-foundation.org>,
> > "Dave Chinner" <david@fromorbit.com>,
> > "linux-xfs" <linux-xfs@vger.kernel.org>, "Jens Axboe" <axboe@kernel.dk>,
> > "Nick Piggin" <npiggin@gmail.com>,
> > linux-fsdevel@vger.kernel.org
> > Sent: Wednesday, October 5, 2016 4:05:22 PM
> > Subject: Re: local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT]
> > splice_read reworked)
> > 
> > On Wed, Oct 05, 2016 at 02:57:04PM -0400, CAI Qian wrote:
> > 
> > > Not sure if this related, and there is always a lockdep regards procfs
> > > happened
> > > below unless masking by other lockdep issues before the cgroup hang.
> > > Also,
> > > this
> > > hang is always reproducible.
> > 
> > Sigh...  Let's get the /proc/*/auxv out of the way - this should deal with
> > it:
> So I applied both this and the sanity patch, and both original sanity and the
> proc warnings went away. However, the cgroup hang can still be reproduced as
> well as this new xfs internal error below,

Wait. There is also a lockep happened before the xfs internal error as well.

[ 5839.452325] ======================================================
[ 5839.459221] [ INFO: possible circular locking dependency detected ]
[ 5839.466215] 4.8.0-rc8-splice-fixw-proc+ #4 Not tainted
[ 5839.471945] -------------------------------------------------------
[ 5839.478937] trinity-c220/69531 is trying to acquire lock:
[ 5839.484961]  (&p->lock){+.+.+.}, at: [<ffffffff812ac69c>] seq_read+0x4c/0x3e0
[ 5839.492967] 
but task is already holding lock:
[ 5839.499476]  (sb_writers#8){.+.+.+}, at: [<ffffffff81284be1>] __sb_start_write+0xd1/0xf0
[ 5839.508560] 
which lock already depends on the new lock.

[ 5839.517686] 
the existing dependency chain (in reverse order) is:
[ 5839.526036] 
-> #3 (sb_writers#8){.+.+.+}:
[ 5839.530751]        [<ffffffff810ff174>] lock_acquire+0xd4/0x240
[ 5839.537368]        [<ffffffff810f8f4a>] percpu_down_read+0x4a/0x90
[ 5839.544275]        [<ffffffff81284be1>] __sb_start_write+0xd1/0xf0
[ 5839.551181]        [<ffffffff812a8544>] mnt_want_write+0x24/0x50
[ 5839.557892]        [<ffffffffa04a398f>] ovl_want_write+0x1f/0x30 [overlay]
[ 5839.565577]        [<ffffffffa04a6036>] ovl_do_remove+0x46/0x480 [overlay]
[ 5839.573259]        [<ffffffffa04a64a3>] ovl_unlink+0x13/0x20 [overlay]
[ 5839.580555]        [<ffffffff812918ea>] vfs_unlink+0xda/0x190
[ 5839.586979]        [<ffffffff81293698>] do_unlinkat+0x268/0x2b0
[ 5839.593599]        [<ffffffff8129419b>] SyS_unlinkat+0x1b/0x30
[ 5839.600120]        [<ffffffff81003c9c>] do_syscall_64+0x6c/0x1e0
[ 5839.606836]        [<ffffffff817d4a3f>] return_from_SYSCALL_64+0x0/0x7a
[ 5839.614231] 
-> #2 (&sb->s_type->i_mutex_key#17){++++++}:
[ 5839.620399]        [<ffffffff810ff174>] lock_acquire+0xd4/0x240
[ 5839.627015]        [<ffffffff817d1b77>] down_read+0x47/0x70
[ 5839.633242]        [<ffffffff8128cfd2>] lookup_slow+0xc2/0x1f0
[ 5839.639762]        [<ffffffff8128f6f2>] walk_component+0x172/0x220
[ 5839.646668]        [<ffffffff81290fd6>] link_path_walk+0x1a6/0x620
[ 5839.653574]        [<ffffffff81291a81>] path_openat+0xe1/0xdb0
[ 5839.660092]        [<ffffffff812939e1>] do_filp_open+0x91/0x100
[ 5839.666707]        [<ffffffff81288e06>] do_open_execat+0x76/0x180
[ 5839.673517]        [<ffffffff81288f3b>] open_exec+0x2b/0x50
[ 5839.679743]        [<ffffffff812eccf3>] load_elf_binary+0x2a3/0x10a0
[ 5839.686844]        [<ffffffff81288917>] search_binary_handler+0x97/0x1d0
[ 5839.694331]        [<ffffffff81289ed8>] do_execveat_common.isra.35+0x678/0x9a0
[ 5839.702400]        [<ffffffff8128a4da>] SyS_execve+0x3a/0x50
[ 5839.708726]        [<ffffffff81003c9c>] do_syscall_64+0x6c/0x1e0
[ 5839.715441]        [<ffffffff817d4a3f>] return_from_SYSCALL_64+0x0/0x7a
[ 5839.722833] 
-> #1 (&sig->cred_guard_mutex){+.+.+.}:
[ 5839.728510]        [<ffffffff810ff174>] lock_acquire+0xd4/0x240
[ 5839.735126]        [<ffffffff817cfc66>] mutex_lock_killable_nested+0x86/0x540
[ 5839.743097]        [<ffffffff81301e84>] lock_trace+0x24/0x60
[ 5839.749421]        [<ffffffff8130224d>] proc_pid_syscall+0x2d/0x110
[ 5839.756423]        [<ffffffff81302af0>] proc_single_show+0x50/0x90
[ 5839.763330]        [<ffffffff812ab867>] traverse+0xf7/0x210
[ 5839.769557]        [<ffffffff812ac9eb>] seq_read+0x39b/0x3e0
[ 5839.775884]        [<ffffffff81280573>] do_loop_readv_writev+0x83/0xc0
[ 5839.783179]        [<ffffffff81281a03>] do_readv_writev+0x213/0x230
[ 5839.790181]        [<ffffffff81281a59>] vfs_readv+0x39/0x50
[ 5839.796406]        [<ffffffff81281c12>] do_preadv+0xa2/0xc0
[ 5839.802634]        [<ffffffff81282ec1>] SyS_preadv+0x11/0x20
[ 5839.808963]        [<ffffffff81003c9c>] do_syscall_64+0x6c/0x1e0
[ 5839.815681]        [<ffffffff817d4a3f>] return_from_SYSCALL_64+0x0/0x7a
[ 5839.823075] 
-> #0 (&p->lock){+.+.+.}:
[ 5839.827395]        [<ffffffff810fe69c>] __lock_acquire+0x151c/0x1990
[ 5839.834500]        [<ffffffff810ff174>] lock_acquire+0xd4/0x240
[ 5839.841115]        [<ffffffff817cf3b6>] mutex_lock_nested+0x76/0x450
[ 5839.848219]        [<ffffffff812ac69c>] seq_read+0x4c/0x3e0
[ 5839.854448]        [<ffffffff8131566b>] kernfs_fop_read+0x12b/0x1b0
[ 5839.861451]        [<ffffffff81280573>] do_loop_readv_writev+0x83/0xc0
[ 5839.868742]        [<ffffffff81281a03>] do_readv_writev+0x213/0x230
[ 5839.875744]        [<ffffffff81281a59>] vfs_readv+0x39/0x50
[ 5839.881971]        [<ffffffff812bc55a>] default_file_splice_read+0x1aa/0x2c0
[ 5839.889847]        [<ffffffff812bb913>] do_splice_to+0x73/0x90
[ 5839.896365]        [<ffffffff812bba1b>] splice_direct_to_actor+0xeb/0x220
[ 5839.903950]        [<ffffffff812bbbd9>] do_splice_direct+0x89/0xd0
[ 5839.910857]        [<ffffffff8128261e>] do_sendfile+0x1ce/0x3b0
[ 5839.917470]        [<ffffffff812831df>] SyS_sendfile64+0x6f/0xd0
[ 5839.924184]        [<ffffffff81003c9c>] do_syscall_64+0x6c/0x1e0
[ 5839.930898]        [<ffffffff817d4a3f>] return_from_SYSCALL_64+0x0/0x7a
[ 5839.938286] 
other info that might help us debug this:

[ 5839.947217] Chain exists of:
  &p->lock --> &sb->s_type->i_mutex_key#17 --> sb_writers#8

[ 5839.956615]  Possible unsafe locking scenario:

[ 5839.963218]        CPU0                    CPU1
[ 5839.968269]        ----                    ----
[ 5839.973321]   lock(sb_writers#8);
[ 5839.977046]                                lock(&sb->s_type->i_mutex_key#17);
[ 5839.985037]                                lock(sb_writers#8);
[ 5839.991573]   lock(&p->lock);
[ 5839.994900] 
 *** DEADLOCK ***

[ 5840.001503] 1 lock held by trinity-c220/69531:
[ 5840.006457]  #0:  (sb_writers#8){.+.+.+}, at: [<ffffffff81284be1>] __sb_start_write+0xd1/0xf0
[ 5840.016031] 
stack backtrace:
[ 5840.020891] CPU: 12 PID: 69531 Comm: trinity-c220 Not tainted 4.8.0-rc8-splice-fixw-proc+ #4
[ 5840.030306] Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0044.R00.1501191641 01/19/2015
[ 5840.041660]  0000000000000086 00000000a1ef62f8 ffff8803ca52f7c0 ffffffff813d2ecc
[ 5840.049952]  ffffffff82a41160 ffffffff82a913e0 ffff8803ca52f800 ffffffff811dd630
[ 5840.058245]  ffff8803ca52f840 ffff880392c4ecc8 ffff880392c4e000 0000000000000001
[ 5840.066537] Call Trace:
[ 5840.069266]  [<ffffffff813d2ecc>] dump_stack+0x85/0xc9
[ 5840.075000]  [<ffffffff811dd630>] print_circular_bug+0x1f9/0x207
[ 5840.081701]  [<ffffffff810fe69c>] __lock_acquire+0x151c/0x1990
[ 5840.088208]  [<ffffffff810ff174>] lock_acquire+0xd4/0x240
[ 5840.094232]  [<ffffffff812ac69c>] ? seq_read+0x4c/0x3e0
[ 5840.100061]  [<ffffffff812ac69c>] ? seq_read+0x4c/0x3e0
[ 5840.105891]  [<ffffffff817cf3b6>] mutex_lock_nested+0x76/0x450
[ 5840.112397]  [<ffffffff812ac69c>] ? seq_read+0x4c/0x3e0
[ 5840.118228]  [<ffffffff810fb3e9>] ? __lock_is_held+0x49/0x70
[ 5840.124540]  [<ffffffff812ac69c>] seq_read+0x4c/0x3e0
[ 5840.130175]  [<ffffffff81315540>] ? kernfs_vma_page_mkwrite+0x90/0x90
[ 5840.137360]  [<ffffffff8131566b>] kernfs_fop_read+0x12b/0x1b0
[ 5840.143770]  [<ffffffff81315540>] ? kernfs_vma_page_mkwrite+0x90/0x90
[ 5840.150956]  [<ffffffff81280573>] do_loop_readv_writev+0x83/0xc0
[ 5840.157657]  [<ffffffff81315540>] ? kernfs_vma_page_mkwrite+0x90/0x90
[ 5840.164843]  [<ffffffff81281a03>] do_readv_writev+0x213/0x230
[ 5840.171255]  [<ffffffff81418cf9>] ? __pipe_get_pages+0x24/0x9b
[ 5840.177762]  [<ffffffff813e6f0f>] ? iov_iter_get_pages_alloc+0x19f/0x360
[ 5840.185240]  [<ffffffff810fd5f2>] ? __lock_acquire+0x472/0x1990
[ 5840.191843]  [<ffffffff81281a59>] vfs_readv+0x39/0x50
[ 5840.197478]  [<ffffffff812bc55a>] default_file_splice_read+0x1aa/0x2c0
[ 5840.204763]  [<ffffffff810cba89>] ? __might_sleep+0x49/0x80
[ 5840.210980]  [<ffffffff81349c93>] ? security_file_permission+0xa3/0xc0
[ 5840.218264]  [<ffffffff812bb913>] do_splice_to+0x73/0x90
[ 5840.224190]  [<ffffffff812bba1b>] splice_direct_to_actor+0xeb/0x220
[ 5840.231182]  [<ffffffff812baee0>] ? generic_pipe_buf_nosteal+0x10/0x10
[ 5840.238465]  [<ffffffff812bbbd9>] do_splice_direct+0x89/0xd0
[ 5840.244778]  [<ffffffff8128261e>] do_sendfile+0x1ce/0x3b0
[ 5840.250802]  [<ffffffff812831df>] SyS_sendfile64+0x6f/0xd0
[ 5840.256922]  [<ffffffff81003c9c>] do_syscall_64+0x6c/0x1e0
[ 5840.263042]  [<ffffffff817d4a3f>] entry_SYSCALL64_slow_path+0x25/0x25

   CAI Qian

  reply	other threads:[~2016-10-06 12:26 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160908235521.GL2356@ZenIV.linux.org.uk>
     [not found] ` <20160909015324.GD30056@dastard>
     [not found]   ` <CA+55aFzohsUXj_3BeFNr2t50Wm=G+7toRDEz=Tk7VJqP3n1hXQ@mail.gmail.com>
     [not found]     ` <CA+55aFxrqCng2Qxasc9pyMrKUGFjo==fEaFT1vkH9Lncte3RgQ@mail.gmail.com>
     [not found]       ` <20160909023452.GO2356@ZenIV.linux.org.uk>
     [not found]         ` <CA+55aFwHQMjO4-vtfB9-ytc=o+DRo-HXVGckvXLboUxgpwb7_g@mail.gmail.com>
     [not found]           ` <20160909221945.GQ2356@ZenIV.linux.org.uk>
     [not found]             ` <CA+55aFzTOOB6oEVaaGD0N7Uznk-W9+ULPwzsxS_L_oZqGVSeLA@mail.gmail.com>
     [not found]               ` <20160914031648.GB2356@ZenIV.linux.org.uk>
     [not found]                 ` <20160914133925.2fba4629@roar.ozlabs.ibm.com>
2016-09-18  5:33                   ` xfs_file_splice_read: possible circular locking dependency detected Al Viro
2016-09-19  3:08                     ` Nicholas Piggin
2016-09-19  6:11                       ` Al Viro
2016-09-19  7:26                         ` Nicholas Piggin
     [not found]                 ` <CA+55aFznQaOWoSMNphgGJJWZ=8-odrc0DAUMzfGPQe+_N4UgNA@mail.gmail.com>
     [not found]                   ` <20160914042559.GC2356@ZenIV.linux.org.uk>
     [not found]                     ` <20160917082007.GA6489@ZenIV.linux.org.uk>
     [not found]                       ` <20160917190023.GA8039@ZenIV.linux.org.uk>
2016-09-18 19:31                         ` skb_splice_bits() and large chunks in pipe (was " Al Viro
2016-09-18 20:12                           ` Linus Torvalds
2016-09-18 22:31                             ` Al Viro
2016-09-19  0:18                               ` Linus Torvalds
2016-09-19  0:22                               ` Al Viro
2016-09-20  9:51                                 ` Herbert Xu
2016-09-23 19:00                         ` [RFC][CFT] splice_read reworked Al Viro
2016-09-23 19:01                           ` [PATCH 01/11] fix memory leaks in tracing_buffers_splice_read() Al Viro
2016-09-23 19:02                           ` [PATCH 02/11] splice_to_pipe(): don't open-code wakeup_pipe_readers() Al Viro
2016-09-23 19:02                           ` [PATCH 03/11] splice: switch get_iovec_page_array() to iov_iter Al Viro
2016-09-23 19:03                           ` [PATCH 04/11] splice: lift pipe_lock out of splice_to_pipe() Al Viro
2016-09-23 19:45                             ` Linus Torvalds
2016-09-23 20:10                               ` Al Viro
2016-09-23 20:36                                 ` Linus Torvalds
2016-09-24  3:59                                   ` Al Viro
2016-09-24 17:29                                     ` Al Viro
2016-09-27 15:38                                       ` Nicholas Piggin
2016-09-27 15:53                                       ` Chuck Lever
2016-09-24  3:59                                   ` [PATCH 04/12] " Al Viro
2016-09-26 13:35                                     ` Miklos Szeredi
2016-09-27  4:14                                       ` Al Viro
2016-12-17 19:54                                     ` Andreas Schwab
2016-12-18 19:28                                       ` Linus Torvalds
2016-12-18 19:57                                         ` Andreas Schwab
2016-12-18 20:12                                         ` Al Viro
2016-12-18 20:30                                           ` Al Viro
2016-12-18 22:10                                             ` Linus Torvalds
2016-12-18 22:18                                               ` Al Viro
2016-12-18 22:22                                                 ` Linus Torvalds
2016-12-18 22:49                                               ` Andreas Schwab
2016-12-21 18:56                                               ` Andreas Schwab
2016-12-21 19:12                                                 ` Linus Torvalds
2016-09-24  4:00                                   ` [PATCH 06/12] new helper: add_to_pipe() Al Viro
2016-09-26 13:49                                     ` Miklos Szeredi
2016-09-24  4:01                                   ` [PATCH 10/12] new iov_iter flavour: pipe-backed Al Viro
2016-09-29 20:53                                     ` Miklos Szeredi
2016-09-29 22:50                                       ` Al Viro
2016-09-30  7:30                                         ` Miklos Szeredi
2016-10-03  3:34                                           ` [RFC] O_DIRECT vs EFAULT (was Re: [PATCH 10/12] new iov_iter flavour: pipe-backed) Al Viro
2016-10-03 17:07                                             ` Linus Torvalds
2016-10-03 18:54                                               ` Al Viro
2016-09-24  4:01                                   ` [PATCH 11/12] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-24  4:02                                   ` [PATCH 12/12] switch default_file_splice_read() to use of pipe-backed iov_iter Al Viro
2016-09-23 19:03                           ` [PATCH 05/11] skb_splice_bits(): get rid of callback Al Viro
2016-09-23 19:04                           ` [PATCH 06/11] new helper: add_to_pipe() Al Viro
2016-09-23 19:04                           ` [PATCH 07/11] fuse_dev_splice_read(): switch to add_to_pipe() Al Viro
2016-09-23 19:06                           ` [PATCH 08/11] cifs: don't use memcpy() to copy struct iov_iter Al Viro
2016-09-23 19:08                           ` [PATCH 09/11] fuse_ioctl_copy_user(): don't open-code copy_page_{to,from}_iter() Al Viro
2016-09-26  9:31                             ` Miklos Szeredi
2016-09-23 19:09                           ` [PATCH 10/11] new iov_iter flavour: pipe-backed Al Viro
2016-09-23 19:10                           ` [PATCH 11/11] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-30 13:32                           ` [RFC][CFT] splice_read reworked CAI Qian
2016-09-30 17:42                             ` CAI Qian
2016-09-30 18:33                               ` CAI Qian
2016-10-03  1:37                                 ` Al Viro
2016-10-03 17:49                                   ` CAI Qian
2016-10-04 17:39                                     ` local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked) CAI Qian
2016-10-04 21:42                                       ` tj
2016-10-05 14:09                                         ` CAI Qian
2016-10-05 15:30                                           ` tj
2016-10-05 15:54                                             ` CAI Qian
2016-10-05 18:57                                               ` CAI Qian
2016-10-05 20:05                                                 ` Al Viro
2016-10-06 12:20                                                   ` CAI Qian
2016-10-06 12:25                                                     ` CAI Qian [this message]
2016-10-06 16:11                                                       ` CAI Qian
2016-10-06 17:00                                                         ` Linus Torvalds
2016-10-06 18:12                                                           ` CAI Qian
2016-10-07  9:57                                                           ` Dave Chinner
2016-10-07 15:25                                                             ` Linus Torvalds
2016-10-07  7:08                                                       ` Jan Kara
2016-10-07 14:43                                                         ` CAI Qian
2016-10-07 15:27                                                           ` CAI Qian
2016-10-07 18:56                                                             ` CAI Qian
2016-10-09 21:54                                                               ` Dave Chinner
2016-10-10 14:10                                                                 ` CAI Qian
2016-10-10 20:14                                                                   ` CAI Qian
2016-10-10 21:57                                                                   ` Dave Chinner
2016-10-12 19:50                                                                     ` [bisected] " CAI Qian
2016-10-12 20:59                                                                       ` Dave Chinner
2016-10-13 16:25                                                                         ` CAI Qian
2016-10-13 20:49                                                                           ` Dave Chinner
2016-10-13 20:56                                                                             ` CAI Qian
2016-10-09 21:51                                                           ` Dave Chinner
2016-10-21 15:38                                                         ` [4.9-rc1+] overlayfs lockdep CAI Qian
2016-10-24 12:57                                                           ` Miklos Szeredi
2016-10-07  9:27                                                     ` local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked) Dave Chinner
2016-10-03  1:42                               ` [RFC][CFT] splice_read reworked Al Viro
2016-10-03 14:06                                 ` CAI Qian
2016-10-03 15:20                                   ` CAI Qian
2016-10-03 21:12                                     ` Dave Chinner
2016-10-04 13:57                                       ` CAI Qian
2016-10-03 20:32                                   ` CAI Qian
2016-10-03 20:35                                     ` Al Viro
2016-10-04 13:29                                       ` CAI Qian
2016-10-04 14:28                                         ` Al Viro
2016-10-04 16:21                                           ` CAI Qian
2016-10-04 20:12                                             ` Al Viro
2016-10-05 14:30                                               ` CAI Qian
2016-10-05 16:07                                                 ` Al Viro

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1860793605.807021.1475756759147.JavaMail.zimbra@redhat.com \
    --to=caiqian@redhat.com \
    --cc=axboe@kernel.dk \
    --cc=david@fromorbit.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=npiggin@gmail.com \
    --cc=tj@kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@ZenIV.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).