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KASAN: slab-out-of-bounds Write in try_module_get

Status: premoderation: reported on 2025/05/03 17:24
Reported-by: syzbot+f312428775d295764222@syzkaller.appspotmail.com
First crash: 70d, last: 1d16h
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Write in try_module_get modules 23 3 1d21h 88d 0/29 moderation: reported on 2025/04/15 15:23

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: slab-out-of-bounds in atomic_inc_not_zero include/asm-generic/atomic-instrumented.h:798 [inline]
BUG: KASAN: slab-out-of-bounds in try_module_get+0x56/0x180 kernel/module.c:1142
Write of size 4 at addr ffff88810963e9a8 by task syz.1.6856/23042

CPU: 1 PID: 23042 Comm: syz.1.6856 Tainted: G        W         5.10.238-syzkaller-00008-g59e9a7228857 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_inc_not_zero include/asm-generic/atomic-instrumented.h:798 [inline]
 try_module_get+0x56/0x180 kernel/module.c:1142
 get_disk_and_module block/genhd.c:1790 [inline]
 exact_lock+0x6a/0xc0 block/genhd.c:677
 kobj_lookup+0x298/0x430 drivers/base/map.c:119
 get_gendisk+0xe9/0x340 block/genhd.c:1001
 bdev_get_gendisk fs/block_dev.c:1110 [inline]
 __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474
 blkdev_get fs/block_dev.c:1653 [inline]
 blkdev_get_by_path+0x253/0x470 fs/block_dev.c:1690
 mount_bdev+0x50/0x3a0 fs/super.c:1400
 vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1057
 legacy_get_tree+0xed/0x190 fs/fs_context.c:593
 vfs_get_tree+0x89/0x260 fs/super.c:1572
 do_new_mount+0x25a/0xa20 fs/namespace.c:2915
 path_mount+0x572/0xc80 fs/namespace.c:3245
 do_mount fs/namespace.c:3258 [inline]
 __do_sys_mount fs/namespace.c:3466 [inline]
 __se_sys_mount+0x318/0x380 fs/namespace.c:3443
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3443
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f87d61da929
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:00007f87d4843038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f87d6401fa0 RCX: 00007f87d61da929
RDX: 0000200000001200 RSI: 00002000000000c0 RDI: 00002000000001c0
RBP: 00007f87d625cb39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f87d6401fa0 R15: 00007fff12193d88

Allocated by task 14885:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 __kmalloc+0x1a7/0x330 mm/slub.c:4033
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 __register_sysctl_table+0xeb/0x1250 fs/proc/proc_sysctl.c:1319
 register_net_sysctl+0x2c/0x40 net/sysctl_net.c:121
 __addrconf_sysctl_register+0x26e/0x3d0 net/ipv6/addrconf.c:7049
 addrconf_sysctl_register+0x147/0x1a0 net/ipv6/addrconf.c:7096
 ipv6_add_dev+0xbaf/0x10a0 net/ipv6/addrconf.c:448
 addrconf_notify+0x582/0xe90 net/ipv6/addrconf.c:3567
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers+0x111/0x190 net/core/dev.c:2080
 register_netdevice+0x1043/0x13c0 net/core/dev.c:10087
 veth_newlink+0x853/0xbb0 drivers/net/veth.c:1387
 __rtnl_newlink net/core/rtnetlink.c:3482 [inline]
 rtnl_newlink+0x11bd/0x1640 net/core/rtnetlink.c:3530
 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2485
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628
 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline]
 netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1333
 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 __sys_sendto+0x41d/0x580 net/socket.c:2006
 __do_sys_sendto net/socket.c:2018 [inline]
 __se_sys_sendto net/socket.c:2014 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2014
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu kernel/rcu/tree.c:2976 [inline]
 call_rcu+0x105/0x1040 kernel/rcu/tree.c:3050
 netlink_release+0x1288/0x1690 net/netlink/af_netlink.c:796
 __sock_release net/socket.c:597 [inline]
 sock_close+0xe0/0x270 net/socket.c:1286
 __fput+0x2fb/0x770 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xa27/0x2470 kernel/exit.c:863
 do_group_exit+0x141/0x310 kernel/exit.c:985
 __do_sys_exit_group kernel/exit.c:996 [inline]
 __se_sys_exit_group kernel/exit.c:994 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:994
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff88810963e000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 424 bytes to the right of
 2048-byte region [ffff88810963e000, ffff88810963e800)
The buggy address belongs to the page:
page:ffffea0004258e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109638
head:ffffea0004258e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000200000001 ffff888100042d80
raw: 0000000000000000 0000000000080008 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 1816057730, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972
 kmem_cache_alloc_node_trace include/linux/slab.h:440 [inline]
 kmalloc_node include/linux/slab.h:570 [inline]
 kzalloc_node include/linux/slab.h:675 [inline]
 __alloc_disk_node+0x79/0x580 block/genhd.c:1727
 loop_add+0x33f/0x7b0 drivers/block/loop.c:2158
 loop_init+0x1bf/0x1ff drivers/block/loop.c:2403
 do_one_initcall+0x187/0x510 init/main.c:1197
 do_initcall_level+0x16f/0x2cf init/main.c:1270
 do_initcalls+0x50/0x92 init/main.c:1286
 do_basic_setup+0x88/0x8f init/main.c:1306
 kernel_init_freeable+0x287/0x3be init/main.c:1510
 kernel_init+0x11/0x1a0 init/main.c:1397
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810963e880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810963e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810963e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff88810963ea00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810963ea80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/11 10:14 android13-5.10-lts 59e9a7228857 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/07/03 14:26 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/28 14:43 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/22 02:28 android13-5.10-lts d76d4cd0623a d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/21 22:43 android13-5.10-lts d76d4cd0623a d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/17 01:36 android13-5.10-lts d76d4cd0623a cfebc887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/16 08:29 android13-5.10-lts d76d4cd0623a 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/06/15 19:41 android13-5.10-lts d76d4cd0623a 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/05/05 09:33 android13-5.10-lts ab07aeb2c93d b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
2025/05/03 17:23 android13-5.10-lts ab07aeb2c93d b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Write in try_module_get
* Struck through repros no longer work on HEAD.