oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=test,mems_allowed=0-1,oom_memcg=/syz0/test,task_memcg=/syz0/test,task=syz.0.17,pid=5933,uid=0
Memory cgroup out of memory: Killed process 5933 (syz.0.17) total-vm:44920kB, anon-rss:1364kB, file-rss:1152kB, shmem-rss:0kB, UID:0 pgtables:80kB oom_score_adj:1000
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in page_ref_count include/linux/page_ref.h:67 [inline]
BUG: KASAN: null-ptr-deref in put_page_testzero include/linux/mm.h:1110 [inline]
BUG: KASAN: null-ptr-deref in folio_put_testzero include/linux/mm.h:1116 [inline]
BUG: KASAN: null-ptr-deref in folio_put include/linux/mm.h:1491 [inline]
BUG: KASAN: null-ptr-deref in ext4_mb_load_buddy_gfp+0x603/0x1760 fs/ext4/mballoc.c:1745
Read of size 4 at addr 0000000000000028 by task syz.0.17/5933

CPU: 1 PID: 5933 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 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 include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 page_ref_count include/linux/page_ref.h:67 [inline]
 put_page_testzero include/linux/mm.h:1110 [inline]
 folio_put_testzero include/linux/mm.h:1116 [inline]
 folio_put include/linux/mm.h:1491 [inline]
 ext4_mb_load_buddy_gfp+0x603/0x1760 fs/ext4/mballoc.c:1745
 ext4_mb_load_buddy fs/ext4/mballoc.c:1757 [inline]
 ext4_mb_regular_allocator+0x1205/0x36c0 fs/ext4/mballoc.c:2937
 ext4_mb_new_blocks+0xc9c/0x42f0 fs/ext4/mballoc.c:6254
 ext4_ext_map_blocks+0x1811/0x68c0 fs/ext4/extents.c:4416
 ext4_map_blocks+0x9db/0x1a90 fs/ext4/inode.c:654
 ext4_getblk+0x1c9/0x720 fs/ext4/inode.c:864
 ext4_bread+0x2a/0x170 fs/ext4/inode.c:920
 ext4_init_symlink_block fs/ext4/namei.c:3395 [inline]
 ext4_symlink+0x519/0x940 fs/ext4/namei.c:3472
 vfs_symlink+0x138/0x2b0 fs/namei.c:4528
 do_symlinkat+0x1ba/0x400 fs/namei.c:4554
 __do_sys_symlinkat fs/namei.c:4570 [inline]
 __se_sys_symlinkat fs/namei.c:4567 [inline]
 __x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4567
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f55d299e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe25dabae8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f55d2c25fa0 RCX: 00007f55d299e0d9
RDX: 00002000000005c0 RSI: ffffffffffffff9c RDI: 0000200000000700
RBP: 00007f55d2a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55d2c25fac R14: 00007f55d2c25fa0 R15: 00007f55d2c25fa0
 </TASK>
==================================================================