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Date: Mon, 11 Mar 2024 07:34:21 -0700
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Subject: Re: [syzbot] [serial?] KASAN: slab-use-after-free Read in
 tty_write_room (2)
From: syzbot <syzbot+2a81fdd5c6ddffee3894@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, jirislaby@kernel.org, 
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, 
	syzkaller-bugs@googlegroups.com
Content-Type: text/plain; charset="UTF-8"

syzbot has found a reproducer for the following issue on:

HEAD commit:    e8f897f4afef Linux 6.8
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1729f41a180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=aba47157efb89052
dashboard link: https://syzkaller.appspot.com/bug?extid=2a81fdd5c6ddffee3894
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11f338d1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/aa5aa46d901e/disk-e8f897f4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1c87fe0fa468/vmlinux-e8f897f4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/94beb1f39151/bzImage-e8f897f4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2a81fdd5c6ddffee3894@syzkaller.appspotmail.com

ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
==================================================================
BUG: KASAN: slab-use-after-free in tty_write_room+0x35/0x90 drivers/tty/tty_ioctl.c:68
Read of size 8 at addr ffff88801f7e6020 by task aoe_tx0/1238

CPU: 1 PID: 1238 Comm: aoe_tx0 Not tainted 6.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x167/0x540 mm/kasan/report.c:488
 kasan_report+0x142/0x180 mm/kasan/report.c:601
 tty_write_room+0x35/0x90 drivers/tty/tty_ioctl.c:68
 handle_tx+0x164/0x640 drivers/net/caif/caif_serial.c:226
 __netdev_start_xmit include/linux/netdevice.h:4986 [inline]
 netdev_start_xmit include/linux/netdevice.h:5000 [inline]
 xmit_one net/core/dev.c:3547 [inline]
 dev_hard_start_xmit+0x244/0x770 net/core/dev.c:3563
 __dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4351
 dev_queue_xmit include/linux/netdevice.h:3169 [inline]
 tx+0x6a/0x110 drivers/block/aoe/aoenet.c:62
 kthread+0x23b/0x440 drivers/block/aoe/aoecmd.c:1229
 kthread+0x2f1/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243
 </TASK>

Allocated by task 8605:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace+0x1d6/0x360 mm/slub.c:4012
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 alloc_tty_struct+0xa9/0x7d0 drivers/tty/tty_io.c:3116
 tty_init_dev+0x5b/0x4c0 drivers/tty/tty_io.c:1415
 ptmx_open+0xda/0x2c0 drivers/tty/pty.c:824
 chrdev_open+0x5b2/0x630 fs/char_dev.c:414
 do_dentry_open+0x909/0x15a0 fs/open.c:953
 do_open fs/namei.c:3645 [inline]
 path_openat+0x285f/0x3240 fs/namei.c:3802
 do_filp_open+0x234/0x490 fs/namei.c:3829
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_openat fs/open.c:1435 [inline]
 __se_sys_openat fs/open.c:1430 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1430
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 5161:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:589
 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kfree+0x14a/0x380 mm/slub.c:4409
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x915/0x1420 kernel/workqueue.c:2706
 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
 kthread+0x2f1/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:551
 insert_work+0x3e/0x330 kernel/workqueue.c:1653
 __queue_work+0xbf4/0x1000 kernel/workqueue.c:1802
 queue_work_on+0x14f/0x250 kernel/workqueue.c:1837
 tty_release_struct+0xbc/0xe0 drivers/tty/tty_io.c:1707
 tty_release+0xd0c/0x12c0 drivers/tty/tty_io.c:1867
 __fput+0x42b/0x8a0 fs/file_table.c:376
 __do_sys_close fs/open.c:1554 [inline]
 __se_sys_close fs/open.c:1539 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1539
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff88801f7e6000
 which belongs to the cache kmalloc-cg-2k of size 2048
The buggy address is located 32 bytes inside of
 freed 2048-byte region [ffff88801f7e6000, ffff88801f7e6800)

The buggy address belongs to the physical page:
page:ffffea00007df800 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801f7e5000 pfn:0x1f7e0
head:ffffea00007df800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880217f6b81
flags: 0xfff00000000a40(workingset|slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000a40 ffff888014c4f3c0 ffffea0001ae3e10 ffffea0001ac3610
raw: ffff88801f7e5000 0000000000080006 00000001ffffffff ffff8880217f6b81
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5098, tgid 5098 (syz-executor.4), ts 200401248275, free_ts 200027547453
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
 prep_new_page mm/page_alloc.c:1540 [inline]
 get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
 __alloc_pages+0x255/0x680 mm/page_alloc.c:4569
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page+0x5f/0x160 mm/slub.c:2190
 allocate_slab mm/slub.c:2354 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2407
 ___slab_alloc+0xd17/0x13e0 mm/slub.c:3540
 __slab_alloc mm/slub.c:3625 [inline]
 __slab_alloc_node mm/slub.c:3678 [inline]
 slab_alloc_node mm/slub.c:3850 [inline]
 __do_kmalloc_node mm/slub.c:3980 [inline]
 __kmalloc_node+0x2d6/0x4e0 mm/slub.c:3988
 kmalloc_node include/linux/slab.h:610 [inline]
 kvmalloc_node+0x72/0x190 mm/util.c:617
 kvmalloc include/linux/slab.h:728 [inline]
 kvmalloc_array include/linux/slab.h:746 [inline]
 alloc_fdtable+0xe7/0x280 fs/file.c:136
 dup_fd+0x839/0xc50 fs/file.c:354
 copy_files+0x14f/0x2a0 kernel/fork.c:1789
 copy_process+0x1c14/0x3fc0 kernel/fork.c:2485
 kernel_clone+0x21d/0x8d0 kernel/fork.c:2902
 __do_sys_clone kernel/fork.c:3045 [inline]
 __se_sys_clone kernel/fork.c:3029 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:3029
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
page last free pid 5111 tgid 5111 stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1140 [inline]
 free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2346
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
 __slab_free+0x349/0x410 mm/slub.c:4211
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc_lru+0x172/0x350 mm/slub.c:3879
 alloc_inode_sb include/linux/fs.h:3018 [inline]
 alloc_inode fs/inode.c:262 [inline]
 new_inode_pseudo+0x8b/0x1e0 fs/inode.c:1005
 new_inode+0x22/0x1d0 fs/inode.c:1031
 debugfs_get_inode fs/debugfs/inode.c:72 [inline]
 __debugfs_create_file+0x14d/0x490 fs/debugfs/inode.c:437
 add_sta_files net/mac80211/debugfs_netdev.c:850 [inline]
 add_files net/mac80211/debugfs_netdev.c:959 [inline]
 ieee80211_debugfs_add_netdev net/mac80211/debugfs_netdev.c:1012 [inline]
 ieee80211_debugfs_recreate_netdev+0xc5a/0x1400 net/mac80211/debugfs_netdev.c:1045
 ieee80211_if_add+0x988/0x1770 net/mac80211/iface.c:2169
 ieee80211_register_hw+0x2fc7/0x3b80 net/mac80211/main.c:1418
 mac80211_hwsim_new_radio+0x250e/0x4400 drivers/net/wireless/virtual/mac80211_hwsim.c:5329
 hwsim_new_radio_nl+0xe4c/0x21d0 drivers/net/wireless/virtual/mac80211_hwsim.c:6010
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1113 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1193 [inline]
 genl_rcv_msg+0xad8/0xe50 net/netlink/genetlink.c:1208

Memory state around the buggy address:
 ffff88801f7e5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801f7e5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801f7e6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88801f7e6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801f7e6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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