d6124d6ba6
the following script:
# tc qdisc add dev crash0 clsact
# tc filter add dev crash0 egress matchall \
> action police rate 3mbit burst 250k pass index 90
# tc actions replace action police \
> rate 3mbit burst 250k goto chain 42 index 90 cookie c1a0c1a0
# tc actions show action police rate 3mbit burst
had the following output:
Error: Failed to init TC action chain.
We have an error talking to the kernel
total acts 1
action order 0: police 0x5a rate 3Mbit burst 250Kb mtu 2Kb action goto chain 42 overhead 0b
ref 2 bind 1
cookie c1a0c1a0
Then, when crash0 starts transmitting more than 3Mbit/s, the following
kernel crash is observed:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
#PF error: [normal kernel read fault]
PGD 800000007a779067 P4D 800000007a779067 PUD 2ad96067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 5032 Comm: netperf Not tainted 5.0.0-rc4.gotochain_crash+ #533
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:tcf_action_exec+0xb8/0x100
Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3
RSP: 0018:ffffb0e04064fa60 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff93bb3322cce0 RCX: 0000000000000005
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff93bb3322cce0
RBP: ffffb0e04064fb00 R08: 0000000000000022 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff93bb3beed300
R13: ffff93bb3beed308 R14: 0000000000000001 R15: ffff93bb3b64d000
FS: 00007f0bc6be5740(0000) GS:ffff93bb3db80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000746a8001 CR4: 00000000001606e0
Call Trace:
tcf_classify+0x58/0x120
__dev_queue_xmit+0x40a/0x890
? ipt_do_table+0x31c/0x420 [ip_tables]
? ip_finish_output2+0x16f/0x430
ip_finish_output2+0x16f/0x430
? ip_output+0x69/0xe0
ip_output+0x69/0xe0
? ip_forward_options+0x1a0/0x1a0
__tcp_transmit_skb+0x563/0xa40
tcp_write_xmit+0x243/0xfa0
__tcp_push_pending_frames+0x32/0xf0
tcp_sendmsg_locked+0x404/0xd30
tcp_sendmsg+0x27/0x40
sock_sendmsg+0x36/0x40
__sys_sendto+0x10e/0x140
? __sys_connect+0x87/0xf0
? syscall_trace_enter+0x1df/0x2e0
? __audit_syscall_exit+0x216/0x260
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x5b/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f0bc5ffbafd
Code: 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 8b 05 ae c4 2c 00 85 c0 75 2d 45 31 c9 45 31 c0 4c 63 d1 48 63 ff b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 63 63 2c 00 f7 d8 64 89 02 48
RSP: 002b:00007fffef94b7f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000004000 RCX: 00007f0bc5ffbafd
RDX: 0000000000004000 RSI: 00000000017e5420 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000017e51d0 R14: 0000000000000010 R15: 0000000000000006
Modules linked in: act_police veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 snd_hda_codec_generic mbcache crct10dif_pclmul jbd2 crc32_pclmul ghash_clmulni_intel snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd glue_helper snd_timer snd joydev pcspkr virtio_balloon soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm virtio_blk virtio_net virtio_console net_failover failover crc32c_intel ata_piix libata serio_raw virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000
Validating the control action within tcf_police_init() proved to fix the
above issue. A TDC selftest is added to verify the correct behavior.
Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.