SRU request submitted:
https://lists.ubuntu.com/archives/kernel-team/2018-June/092921.html
** Description changed:
+ == SRU Justification ==
+ Artful is missing commit a90bcb86ae70, which was sent
+ to upstream stable. Since upstream 4.13 is EOL, Artful never got it.
+
+ Because Artful does not have this commit when receiving large UDP packages
+ with a small MTU there are backtraces, examples posted in the bug.
+
+ Commit a90bcb86ae70 is in mainline as ov v4.14-rc2 and is only needed in
+ Artful.
+
+ == Fix ==
+ a90bcb86ae70 ("iov_iter: fix page_copy_sane for compound pages")
+
+ == Regression Potential ==
+ Low. This commit fixes a current regression in Artful. It was also
+ cc'd to stable, so it has had additional upstream review.
+
+ == Test Case ==
+ A test kernel was built with this patch and tested by the original bug
reporter.
+ The bug reporter states the test kernel resolved the bug.
+
+
+
+
+
+
kernel 4.13.0-41-generic is missing commit a90bcb86ae70:
Author: Petar Penkov <[email protected]>
Date: Tue Aug 29 11:20:32 2017 -0700
- iov_iter: fix page_copy_sane for compound pages
-
- Issue is that if the data crosses a page boundary inside a compound
- page, this check will incorrectly trigger a WARN_ON.
-
- To fix this, compute the order using the head of the compound page and
- adjust the offset to be relative to that head.
-
- Fixes: 72e809ed81ed ("iov_iter: sanity checks for copy to/from page
- primitives")
-
- Signed-off-by: Petar Penkov <[email protected]>
- CC: Al Viro <[email protected]>
- CC: Eric Dumazet <[email protected]>
- Signed-off-by: Al Viro <[email protected]>
+ iov_iter: fix page_copy_sane for compound pages
+
+ Issue is that if the data crosses a page boundary inside a compound
+ page, this check will incorrectly trigger a WARN_ON.
+
+ To fix this, compute the order using the head of the compound page and
+ adjust the offset to be relative to that head.
+
+ Fixes: 72e809ed81ed ("iov_iter: sanity checks for copy to/from page
+ primitives")
+
+ Signed-off-by: Petar Penkov <[email protected]>
+ CC: Al Viro <[email protected]>
+ CC: Eric Dumazet <[email protected]>
+ Signed-off-by: Al Viro <[email protected]>
Commit 72e809ed81ed is in kernel 4.13.0-41-generic.
As a result, when receiving large UDP packages with a small MTU we get
backtraces like:
[ 361.260969] ------------[ cut here ]------------
[ 361.260974] WARNING: CPU: 4 PID: 2541 at
/build/linux-hwe-v6kHHF/linux-hwe-4.13.0/lib/iov_iter.c:693
copy_page_to_iter+0x194/0x2d0
[ 361.260975] Modules linked in: cmdlinepart sfc(OE) hwmon_vid crc32_generic
mii rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace fscache 8021q garp mrp
stp llc intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
i]
[ 361.261002] CPU: 4 PID: 2541 Comm: udp_recv Tainted: G OE
4.13.0-39-generic #44~16.04.1-Ubuntu
[ 361.261003] Hardware name: Dell Inc. PowerEdge R220/05Y15N, BIOS 1.4.0
10/23/2014
[ 361.261004] task: ffff91630b2bae80 task.stack: ffffbb19c2bfc000
[ 361.261005] RIP: 0010:copy_page_to_iter+0x194/0x2d0
[ 361.261006] RSP: 0018:ffffbb19c2bffc60 EFLAGS: 00010202
[ 361.261007] RAX: 0000000000001000 RBX: 00000000000000df RCX:
0017ffffc0000000
[ 361.261008] RDX: 00000000000000df RSI: 0000000000000f8e RDI:
fffff666895279c0
[ 361.261009] RBP: ffffbb19c2bffca0 R08: 000000000000106d R09:
0000000000001024
[ 361.261009] R10: 0000000000000000 R11: ffff91630ccc9b00 R12:
ffff91630d27a300
[ 361.261010] R13: ffffbb19c2bffde0 R14: 00000000000000df R15:
0000000000000175
[ 361.261011] FS: 00007fb8e7649700(0000) GS:ffff91631fd00000(0000)
knlGS:0000000000000000
[ 361.261012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 361.261013] CR2: 000014588da85624 CR3: 000000024bad2002 CR4:
00000000001606e0
[ 361.261013] Call Trace:
[ 361.261017] ? proto_init_net+0x40/0x40
[ 361.261019] skb_copy_datagram_iter+0x171/0x270
[ 361.261022] udp_recvmsg+0x108/0x490
[ 361.261024] inet_recvmsg+0x51/0xc0
[ 361.261026] sock_recvmsg+0x43/0x50
[ 361.261028] sock_read_iter+0x90/0xe0
[ 361.261030] new_sync_read+0xe2/0x130
[ 361.261032] __vfs_read+0x29/0x40
[ 361.261033] vfs_read+0x93/0x130
[ 361.261034] SyS_read+0x55/0xc0
[ 361.261037] entry_SYSCALL_64_fastpath+0x24/0xab
[ 361.261038] RIP: 0033:0x7fb8e7160260
[ 361.261039] RSP: 002b:00007ffed9dd9e38 EFLAGS: 00000246 ORIG_RAX:
0000000000000000
[ 361.261040] RAX: ffffffffffffffda RBX: 0000000000000000 RCX:
00007fb8e7160260
[ 361.261041] RDX: 000000000000ffe3 RSI: 00005622ad02f0a0 RDI:
0000000000000003
[ 361.261041] RBP: 00007ffed9dd9e70 R08: 0000000000000000 R09:
0000000000000011
[ 361.261042] R10: 0000000000000000 R11: 0000000000000246 R12:
00005622ace2e800
[ 361.261043] R13: 00007ffed9dd9f50 R14: 0000000000000000 R15:
0000000000000000
- [ 361.261044] Code: de 4c 89 e7 e8 be fa ff ff 41 83 af a0 12 00 00 01 48 83
c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 8b 4f 6c 48 d3 e0 e9 9d fe ff ff <0f> ff
48 83 c4 18 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 49 83
+ [ 361.261044] Code: de 4c 89 e7 e8 be fa ff ff 41 83 af a0 12 00 00 01 48 83
c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 8b 4f 6c 48 d3 e0 e9 9d fe ff ff <0f> ff
48 83 c4 18 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 49 83
[ 361.261064] ---[ end trace c0b23bf37be9874d ]---
This is a request to pull in commit a90bcb86ae70.
# lsb_release -rd
Description: Ubuntu 17.10
Release: 17.10
# uname -a
Linux c6320f 4.13.0-41-generic #46-Ubuntu SMP Wed May 2 13:38:30 UTC 2018
x86_64 x86_64 x86_64 GNU/Linux
- # cat /proc/version_signature
+ # cat /proc/version_signature
Ubuntu 4.13.0-41.46-generic 4.13.16
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https://bugs.launchpad.net/bugs/1772031
Title:
kernel backtrace when receiving large UDP packages
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