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KASAN: slab-out-of-bounds Write in try_module_get (2)

Status: upstream: reported on 2026/02/06 18:05
Subsystems: modules
[Documentation on labels]
Reported-by: syzbot+e993e01b15c8eefd9cd4@syzkaller.appspotmail.com
First crash: 80d, last: 2h57m
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [modules?] KASAN: slab-out-of-bounds Write in try_module_get (2) 0 (1) 2026/02/06 18:05
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: slab-out-of-bounds Write in try_module_get 21 11 210d 281d 0/2 auto-obsoleted due to no activity on 2025/10/12 05:38
upstream KASAN: slab-out-of-bounds Write in try_module_get modules 21 4 175d 299d 0/29 auto-obsoleted due to no activity on 2025/11/15 19:20

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-out-of-bounds in atomic_inc_not_zero include/linux/atomic/atomic-instrumented.h:1536 [inline]
BUG: KASAN: slab-out-of-bounds in try_module_get+0x46/0xc0 kernel/module/main.c:913
Write of size 4 at addr ffff888142f67108 by task syz.3.2706/18556

CPU: 1 UID: 0 PID: 18556 Comm: syz.3.2706 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_inc_not_zero include/linux/atomic/atomic-instrumented.h:1536 [inline]
 try_module_get+0x46/0xc0 kernel/module/main.c:913
 dvb_device_open+0xef/0x350 drivers/media/dvb-core/dvbdev.c:103
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:414
 do_dentry_open+0x7ce/0x1420 fs/open.c:962
 vfs_open+0x3b/0x340 fs/open.c:1094
 do_open fs/namei.c:4637 [inline]
 path_openat+0x3486/0x3e20 fs/namei.c:4796
 do_filp_open+0x22d/0x490 fs/namei.c:4823
 do_sys_openat2+0x12f/0x220 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feefad5b78e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007feefbc79b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007feefbc7a6c0 RCX: 00007feefad5b78e
RDX: 0000000000000002 RSI: 00007feefbc79c00 RDI: ffffffffffffff9c
RBP: 00007feefbc79c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007feefb016128 R14: 00007feefb016090 R15: 00007ffc341cef58
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_dmxdev_init+0x31d/0x440 drivers/media/dvb-core/dmxdev.c:1436
 vidtv_bridge_dmxdev_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:343 [inline]
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:445 [inline]
 vidtv_bridge_probe+0xb5f/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0xf9/0x190 drivers/base/platform.c:1446
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:661
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
 __driver_attach+0x349/0x640 drivers/base/dd.c:1227
 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x345/0x670 drivers/base/bus.c:715
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x250/0x840 init/main.c:1378
 do_initcall_level+0x104/0x190 init/main.c:1440
 do_initcalls+0x59/0xa0 init/main.c:1456
 kernel_init_freeable+0x2a6/0x3d0 init/main.c:1688
 kernel_init+0x1d/0x1d0 init/main.c:1578
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

The buggy address belongs to the object at ffff888142f67000
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 48 bytes to the right of
 allocated 216-byte region [ffff888142f67000, ffff888142f670d8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x142f66
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88813fe26b40 ffffea0001ee1c00 0000000000000006
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88813fe26b40 ffffea0001ee1c00 0000000000000006
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000001 ffffea00050bd981 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 18467899701, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3a0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xd82/0x1760 mm/slub.c:4656
 __slab_alloc+0x65/0x100 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __kmalloc_cache_noprof+0x40d/0x6e0 mm/slub.c:5775
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 bus_add_driver+0x162/0x670 drivers/base/bus.c:699
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
 pvr_init+0x4c/0xb0 drivers/media/usb/pvrusb2/pvrusb2-main.c:112
 do_one_initcall+0x250/0x840 init/main.c:1378
 do_initcall_level+0x104/0x190 init/main.c:1440
 do_initcalls+0x59/0xa0 init/main.c:1456
 kernel_init_freeable+0x2a6/0x3d0 init/main.c:1688
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888142f67000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888142f67080: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
>ffff888142f67100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff888142f67180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888142f67200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/08 16:36 upstream e7aa57247700 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-out-of-bounds Write in try_module_get
2026/02/08 04:51 upstream e7aa57247700 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-out-of-bounds Write in try_module_get
2025/11/20 20:06 upstream 8e621c9a3375 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-out-of-bounds Write in try_module_get
2026/02/09 03:38 upstream e98f34af6116 4c131dc4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Write in try_module_get
2026/02/07 08:40 upstream 2687c848e578 f20fc9f9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Write in try_module_get
2026/02/06 11:57 upstream b7ff7151e653 97745f52 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Write in try_module_get
2026/02/07 00:13 upstream 2687c848e578 f20fc9f9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-out-of-bounds Write in try_module_get
2026/02/06 18:04 linux-next 9845cf73f7db 97745f52 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: slab-out-of-bounds Write in try_module_get
2026/02/07 17:21 upstream 2687c848e578 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root general protection fault in try_module_get
2025/12/07 16:57 upstream 37bb2e7217b0 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto general protection fault in try_module_get
2026/02/08 14:47 upstream e7aa57247700 4c131dc4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in try_module_get
2026/02/06 11:57 upstream b7ff7151e653 97745f52 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in try_module_get
* Struck through repros no longer work on HEAD.