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

Status: upstream: reported on 2026/03/03 08:42
Reported-by: syzbot+e263ad37dc7cc04260cb@syzkaller.appspotmail.com
First crash: 54d, last: 54d
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: slab-out-of-bounds Write in try_module_get 21 8 51d 74d 0/3 upstream: reported on 2026/02/11 05:44
linux-5.15 KASAN: slab-out-of-bounds Write in try_module_get 21 3 16d 54d 0/3 upstream: reported on 2026/03/02 19:08
android-5-10 KASAN: slab-out-of-bounds Write in try_module_get 21 11 286d 357d 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 251d 375d 0/29 auto-obsoleted due to no activity on 2025/11/15 19:20
upstream KASAN: slab-out-of-bounds Write in try_module_get (2) modules 22 160 12h01m 78d 0/29 upstream: reported on 2026/02/06 18:05

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:1525 [inline]
BUG: KASAN: slab-out-of-bounds in try_module_get+0x46/0xc0 kernel/module/main.c:837
Write of size 4 at addr ffff888145670af8 by task syz.4.176/6672

CPU: 0 PID: 6672 Comm: syz.4.176 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x241/0x290 mm/kasan/generic.c:187
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_inc_not_zero include/linux/atomic/atomic-instrumented.h:1525 [inline]
 try_module_get+0x46/0xc0 kernel/module/main.c:837
 dvb_device_open+0xf5/0x370 drivers/media/dvb-core/dvbdev.c:103
 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3640 [inline]
 path_openat+0x27f1/0x3230 fs/namei.c:3797
 do_filp_open+0x1f5/0x430 fs/namei.c:3824
 do_sys_openat2+0x134/0x1d0 fs/open.c:1421
 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+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0b11d5cfce
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:00007f0b0fb90b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0b0fb916c0 RCX: 00007f0b11d5cfce
RDX: 0000000000000e82 RSI: 00007f0b0fb90c00 RDI: ffffffffffffff9c
RBP: 00007f0b0fb90c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f0b12016308 R14: 00007f0b12016270 R15: 00007ffd4a00b928
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_dmxdev_init+0x30c/0x420 drivers/media/dvb-core/dmxdev.c:1435
 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+0xb60/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0x13b/0x1c0 drivers/base/platform.c:1404
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x25b/0xb20 drivers/base/dd.c:658
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:830
 __driver_attach+0x44e/0x6e0 drivers/base/dd.c:1216
 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370
 bus_add_driver+0x340/0x630 drivers/base/bus.c:675
 driver_register+0x23a/0x310 drivers/base/driver.c:246
 vidtv_bridge_init+0x3d/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff888145670a00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 32 bytes to the right of
 allocated 216-byte region [ffff888145670a00, ffff888145670ad8)

The buggy address belongs to the physical page:
page:ffffea0005159c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x145670
head:ffffea0005159c00 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000840(slab|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 057ff00000000840 ffff888017c41b40 ffffea0000845000 0000000000000004
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
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 12247424768, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4486
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x19e/0x250 mm/slub.c:3534
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 bus_add_driver+0x162/0x630 drivers/base/bus.c:659
 driver_register+0x23a/0x310 drivers/base/driver.c:246
 i2c_register_driver+0xba/0x160 drivers/i2c/i2c-core-base.c:2016
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888145670980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888145670a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888145670a80: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
                                                                ^
 ffff888145670b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888145670b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/03 08:42 linux-6.6.y 7a137e9bfa0e 28b83e23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Write in try_module_get
* Struck through repros no longer work on HEAD.