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7c4046b1c5
This reverts commit4cda75275ffrom net-next. Brown bag time. Michal noticed that this change doesn't work at all when netif_set_real_num_tx_queues() gets called prior to an initial dev_activate(), as for instance igb does. Doing so dies with: [ 40.579142] BUG: kernel NULL pointer dereference, address: 0000000000000400 [ 40.586922] #PF: supervisor read access in kernel mode [ 40.592668] #PF: error_code(0x0000) - not-present page [ 40.598405] PGD 0 P4D 0 [ 40.601234] Oops: 0000 [#1] PREEMPT SMP PTI [ 40.605909] CPU: 18 PID: 1681 Comm: wickedd Tainted: G E 5.6.0-rc3-ethnl.50-default #1 [ 40.616205] Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.R3.27.D685.1305151734 05/15/2013 [ 40.627377] RIP: 0010:qdisc_hash_add.part.22+0x2e/0x90 [ 40.633115] Code: 00 55 53 89 f5 48 89 fb e8 2f 9b fb ff 85 c0 74 44 48 8b 43 40 48 8b 08 69 43 38 47 86 c8 61 c1 e8 1c 48 83 e8 80 48 8d 14 c1 <48> 8b 04 c1 48 8d 4b 28 48 89 53 30 48 89 43 28 48 85 c0 48 89 0a [ 40.654080] RSP: 0018:ffffb879864934d8 EFLAGS: 00010203 [ 40.659914] RAX: 0000000000000080 RBX: ffffffffb8328d80 RCX: 0000000000000000 [ 40.667882] RDX: 0000000000000400 RSI: 0000000000000000 RDI: ffffffffb831faa0 [ 40.675849] RBP: 0000000000000000 R08: ffffa0752c8b9088 R09: ffffa0752c8b9208 [ 40.683816] R10: 0000000000000006 R11: 0000000000000000 R12: ffffa0752d734000 [ 40.691783] R13: 0000000000000008 R14: 0000000000000000 R15: ffffa07113c18000 [ 40.699750] FS: 00007f94548e5880(0000) GS:ffffa0752e980000(0000) knlGS:0000000000000000 [ 40.708782] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 40.715189] CR2: 0000000000000400 CR3: 000000082b6ae006 CR4: 00000000001606e0 [ 40.723156] Call Trace: [ 40.725888] dev_qdisc_set_real_num_tx_queues+0x61/0x90 [ 40.731725] netif_set_real_num_tx_queues+0x94/0x1d0 [ 40.737286] __igb_open+0x19a/0x5d0 [igb] [ 40.741767] __dev_open+0xbb/0x150 [ 40.745567] __dev_change_flags+0x157/0x1a0 [ 40.750240] dev_change_flags+0x23/0x60 [...] Fixes:4cda75275f("net: sched: make newly activated qdiscs visible") Reported-by: Michal Kubecek <mkubecek@suse.cz> CC: Michal Kubecek <mkubecek@suse.cz> CC: Eric Dumazet <edumazet@google.com> CC: Jamal Hadi Salim <jhs@mojatatu.com> CC: Cong Wang <xiyou.wangcong@gmail.com> CC: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.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.