Message-ID: <67913132.050a0220.15cac.0280.GAE@google.com>
Date: Wed, 22 Jan 2025 09:56:02 -0800
From: syzbot <syzbot+2e5de9e3ab986b71d2bf@...kaller.appspotmail.com>
To: kuba@...nel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net?] WARNING in nsim_udp_tunnel_set_port

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in nsim_udp_tunnels_info_reset_write

==================================================================
BUG: KASAN: slab-use-after-free in nsim_udp_tunnels_info_reset_write+0xf8/0x110 drivers/net/netdevsim/udp_tunnels.c:116
Read of size 8 at addr ffff88805b9f94d8 by task syz.0.4728/17081

CPU: 0 UID: 0 PID: 17081 Comm: syz.0.4728 Not tainted 6.13.0-syzkaller-gc4b9570cfb63-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 nsim_udp_tunnels_info_reset_write+0xf8/0x110 drivers/net/netdevsim/udp_tunnels.c:116
 full_proxy_write+0xfd/0x1b0 fs/debugfs/file.c:369
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc7e585d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbc7f41d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbc7e775fa0 RCX: 00007fbc7e585d29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fbc7e601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fbc7e775fa0 R15: 00007fff9f7d4048
 </TASK>

Allocated by task 11942:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4298 [inline]
 __kmalloc_node_noprof+0x21f/0x520 mm/slub.c:4304
 __kvmalloc_node_noprof+0x6f/0x1a0 mm/util.c:645
 alloc_netdev_mqs+0xc9/0x1320 net/core/dev.c:11228
 nsim_create+0x98/0xb20 drivers/net/netdevsim/netdev.c:777
 __nsim_dev_port_add+0x3bf/0x700 drivers/net/netdevsim/dev.c:1393
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1449 [inline]
 nsim_drv_probe+0xdbf/0x1490 drivers/net/netdevsim/dev.c:1607
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x23e/0xa90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958
 bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459
 __device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
 bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:534
 device_add+0x114b/0x1a70 drivers/base/core.c:3665
 nsim_bus_dev_new drivers/net/netdevsim/bus.c:442 [inline]
 new_device_store+0x41d/0x730 drivers/net/netdevsim/bus.c:173
 bus_attr_store+0x71/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139
 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x5ae/0x1150 fs/read_write.c:679
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 3526:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4613 [inline]
 kfree+0x14f/0x4b0 mm/slub.c:4761
 kvfree+0x47/0x50 mm/util.c:688
 device_release+0xa1/0x240 drivers/base/core.c:2567
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e4/0x5a0 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3773
 free_netdev+0x4f1/0x6c0 net/core/dev.c:11397
 __nsim_dev_port_del+0x189/0x240 drivers/net/netdevsim/dev.c:1428
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1440 [inline]
 nsim_dev_reload_destroy+0x108/0x4d0 drivers/net/netdevsim/dev.c:1661
 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:968
 devlink_reload+0x17f/0x760 net/devlink/dev.c:461
 devlink_pernet_pre_exit+0x1a1/0x2b0 net/devlink/core.c:509
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 cleanup_net+0x488/0xbd0 net/core/net_namespace.c:628
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff88805b9f8000
 which belongs to the cache kmalloc-cg-8k of size 8192
The buggy address is located 5336 bytes inside of
 freed 8192-byte region [ffff88805b9f8000, ffff88805b9fa000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5b9f8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880296446c1
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b04f640 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000020002 00000001f5000000 ffff8880296446c1
head: 00fff00000000040 ffff88801b04f640 dead000000000122 0000000000000000
head: 0000000000000000 0000000000020002 00000001f5000000 ffff8880296446c1
head: 00fff00000000003 ffffea00016e7e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11942, tgid 11942 (syz-executor), ts 192560619734, free_ts 192552404020
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1558
 prep_new_page mm/page_alloc.c:1566 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3476
 __alloc_pages_noprof+0x221/0x2470 mm/page_alloc.c:4753
 alloc_pages_mpol_noprof+0x2c8/0x620 mm/mempolicy.c:2269
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2589 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2642
 ___slab_alloc+0xbcd/0x1590 mm/slub.c:3830
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 __do_kmalloc_node mm/slub.c:4297 [inline]
 __kmalloc_node_noprof+0x2f0/0x520 mm/slub.c:4304
 __kvmalloc_node_noprof+0x6f/0x1a0 mm/util.c:645
 alloc_netdev_mqs+0xc9/0x1320 net/core/dev.c:11228
 nsim_create+0x98/0xb20 drivers/net/netdevsim/netdev.c:777
 __nsim_dev_port_add+0x3bf/0x700 drivers/net/netdevsim/dev.c:1393
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1449 [inline]
 nsim_drv_probe+0xdbf/0x1490 drivers/net/netdevsim/dev.c:1607
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x23e/0xa90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
page last free pid 11942 tgid 11942 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0x661/0x1080 mm/page_alloc.c:2659
 __put_partials+0x14c/0x170 mm/slub.c:3157
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:385
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 ref_tracker_alloc+0x17c/0x5b0 lib/ref_tracker.c:203
 __netdev_tracker_alloc include/linux/netdevice.h:4136 [inline]
 netdev_hold include/linux/netdevice.h:4165 [inline]
 netdev_hold include/linux/netdevice.h:4160 [inline]
 register_netdevice+0x164b/0x1e20 net/core/dev.c:10638
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:733 [inline]
 nsim_create+0x740/0xb20 drivers/net/netdevsim/netdev.c:793
 __nsim_dev_port_add+0x3bf/0x700 drivers/net/netdevsim/dev.c:1393
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1449 [inline]
 nsim_drv_probe+0xdbf/0x1490 drivers/net/netdevsim/dev.c:1607
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x23e/0xa90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958
 bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459
 __device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030

Memory state around the buggy address:
 ffff88805b9f9380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805b9f9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805b9f9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88805b9f9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805b9f9580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         c4b9570c Merge tag 'audit-pr-20250121' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1404cab0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c857c6065c39b1e2
dashboard link: https://syzkaller.appspot.com/bug?extid=2e5de9e3ab986b71d2bf
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13c71824580000

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