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module: Make .static_call_sites read-only after init #61

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@modules-kpd-app modules-kpd-app bot commented Mar 6, 2025

Pull request for series with
subject: module: Make .static_call_sites read-only after init
version: 2
url: https://patchwork.kernel.org/project/linux-modules/list/?series=941023

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modules-kpd-app bot commented Mar 6, 2025

Upstream branch: afa9286
series: https://patchwork.kernel.org/project/linux-modules/list/?series=941023
version: 2

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modules-kpd-app bot commented Mar 18, 2025

Upstream branch: 085c5e3
series: https://patchwork.kernel.org/project/linux-modules/list/?series=941023
version: 2

@modules-kpd-app modules-kpd-app bot force-pushed the series/920370=>modules-next branch from 57fe96f to cb823a3 Compare March 18, 2025 22:56
@dkruces dkruces force-pushed the modules-next_base branch from 96f6e22 to 7c2b408 Compare April 1, 2025 10:54
@modules-kpd-app modules-kpd-app bot force-pushed the modules-next_base branch from 7c2b408 to 2996654 Compare April 7, 2025 01:58
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modules-kpd-app bot commented Apr 7, 2025

Upstream branch: 897c0b4
series: https://patchwork.kernel.org/project/linux-modules/list/?series=941023
version: 2

petrpavlu added 3 commits April 7, 2025 01:59
@petrpavlu
module: Constify parameters of module_enforce_rwx_sections()
407d88a 
Minor cleanup, this is a non-functional change.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
@petrpavlu
module: Add a separate function to mark sections as read-only after init
825e04f 
Move the logic to mark special sections as read-only after module
initialization into a separate function, along other related code in
strict_rwx.c. Use a table with names of such sections to make it easier to
add more.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
@petrpavlu
module: Make .static_call_sites read-only after init
d327ee8 
Section .static_call_sites holds data structures that need to be sorted and
processed only at module load time. This initial processing happens in
static_call_add_module(), which is invoked as a callback to the
MODULE_STATE_COMING notification from prepare_coming_module().

The section is never modified afterwards. Make it therefore read-only after
module initialization to avoid any (non-)accidental modifications.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
@modules-kpd-app modules-kpd-app bot force-pushed the series/920370=>modules-next branch from cb823a3 to d327ee8 Compare April 7, 2025 01:59
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dkruces pushed a commit that referenced this pull request Jul 21, 2025
@kuba-moo
net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during…
579d4f9 
… runtime

Assuming the "rx-vlan-filter" feature is enabled on a net device, the
8021q module will automatically add or remove VLAN 0 when the net device
is put administratively up or down, respectively. There are a couple of
problems with the above scheme.

The first problem is a memory leak that can happen if the "rx-vlan-filter"
feature is disabled while the device is running:

 # ip link add bond1 up type bond mode 0
 # ethtool -K bond1 rx-vlan-filter off
 # ip link del dev bond1

When the device is put administratively down the "rx-vlan-filter"
feature is disabled, so the 8021q module will not remove VLAN 0 and the
memory will be leaked [1].

Another problem that can happen is that the kernel can automatically
delete VLAN 0 when the device is put administratively down despite not
adding it when the device was put administratively up since during that
time the "rx-vlan-filter" feature was disabled. null-ptr-unref or
bug_on[2] will be triggered by unregister_vlan_dev() for refcount
imbalance if toggling filtering during runtime:

$ ip link add bond0 type bond mode 0
$ ip link add link bond0 name vlan0 type vlan id 0 protocol 802.1q
$ ethtool -K bond0 rx-vlan-filter off
$ ifconfig bond0 up
$ ethtool -K bond0 rx-vlan-filter on
$ ifconfig bond0 down
$ ip link del vlan0

Root cause is as below:
step1: add vlan0 for real_dev, such as bond, team.
register_vlan_dev
    vlan_vid_add(real_dev,htons(ETH_P_8021Q),0) //refcnt=1
step2: disable vlan filter feature and enable real_dev
step3: change filter from 0 to 1
vlan_device_event
    vlan_filter_push_vids
        ndo_vlan_rx_add_vid //No refcnt added to real_dev vlan0
step4: real_dev down
vlan_device_event
    vlan_vid_del(dev, htons(ETH_P_8021Q), 0); //refcnt=0
        vlan_info_rcu_free //free vlan0
step5: delete vlan0
unregister_vlan_dev
    BUG_ON(!vlan_info); //vlan_info is null

Fix both problems by noting in the VLAN info whether VLAN 0 was
automatically added upon NETDEV_UP and based on that decide whether it
should be deleted upon NETDEV_DOWN, regardless of the state of the
"rx-vlan-filter" feature.

[1]
unreferenced object 0xffff8880068e3100 (size 256):
  comm "ip", pid 384, jiffies 4296130254
  hex dump (first 32 bytes):
    00 20 30 0d 80 88 ff ff 00 00 00 00 00 00 00 00  . 0.............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 81ce31fa):
    __kmalloc_cache_noprof+0x2b5/0x340
    vlan_vid_add+0x434/0x940
    vlan_device_event.cold+0x75/0xa8
    notifier_call_chain+0xca/0x150
    __dev_notify_flags+0xe3/0x250
    rtnl_configure_link+0x193/0x260
    rtnl_newlink_create+0x383/0x8e0
    __rtnl_newlink+0x22c/0xa40
    rtnl_newlink+0x627/0xb00
    rtnetlink_rcv_msg+0x6fb/0xb70
    netlink_rcv_skb+0x11f/0x350
    netlink_unicast+0x426/0x710
    netlink_sendmsg+0x75a/0xc20
    __sock_sendmsg+0xc1/0x150
    ____sys_sendmsg+0x5aa/0x7b0
    ___sys_sendmsg+0xfc/0x180

[2]
kernel BUG at net/8021q/vlan.c:99!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 382 Comm: ip Not tainted 6.16.0-rc3 #61 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:unregister_vlan_dev (net/8021q/vlan.c:99 (discriminator 1))
RSP: 0018:ffff88810badf310 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88810da84000 RCX: ffffffffb47ceb9a
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88810e8b43c8
RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff6cefe80
R10: ffffffffb677f407 R11: ffff88810badf3c0 R12: ffff88810e8b4000
R13: 0000000000000000 R14: ffff88810642a5c0 R15: 000000000000017e
FS:  00007f1ff68c20c0(0000) GS:ffff888163a24000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ff5dad240 CR3: 0000000107e56000 CR4: 00000000000006f0
Call Trace:
 <TASK>
rtnl_dellink (net/core/rtnetlink.c:3511 net/core/rtnetlink.c:3553)
rtnetlink_rcv_msg (net/core/rtnetlink.c:6945)
netlink_rcv_skb (net/netlink/af_netlink.c:2535)
netlink_unicast (net/netlink/af_netlink.c:1314 net/netlink/af_netlink.c:1339)
netlink_sendmsg (net/netlink/af_netlink.c:1883)
____sys_sendmsg (net/socket.c:712 net/socket.c:727 net/socket.c:2566)
___sys_sendmsg (net/socket.c:2622)
__sys_sendmsg (net/socket.c:2652)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)

Fixes: ad1afb0 ("vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)")
Reported-by: syzbot+a8b046e462915c65b10b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a8b046e462915c65b10b
Suggested-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250716034504.2285203-2-dongchenchen2@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
@modules-kpd-app modules-kpd-app bot force-pushed the modules-next_base branch 4 times, most recently from cdc6b9e to 311def7 Compare October 22, 2025 11:40
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