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BUG: KMSAN: uninit-value in __flush_smp_call_function_queue+0x362/0x18e0 kernel/smp.c:535
 __flush_smp_call_function_queue+0x362/0x18e0 kernel/smp.c:535
 generic_smp_call_function_single_interrupt+0x1c/0x30 kernel/smp.c:463
 __sysvec_call_function_single+0x4b/0x3e0 arch/x86/kernel/smp.c:271
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0x7c/0x90 arch/x86/kernel/smp.c:266
 asm_sysvec_call_function_single+0x1f/0x30 arch/x86/include/asm/idtentry.h:704
 kmsan_phys_addr_valid arch/x86/include/asm/kmsan.h:55 [inline]
 kmsan_virt_addr_valid arch/x86/include/asm/kmsan.h:79 [inline]
 virt_to_page_or_null+0x27/0x170 mm/kmsan/shadow.c:75
 kmsan_get_shadow_origin_ptr+0x35/0xb0 mm/kmsan/shadow.c:97
 get_shadow_origin_ptr mm/kmsan/instrumentation.c:38 [inline]
 __msan_metadata_ptr_for_load_8+0x24/0x40 mm/kmsan/instrumentation.c:94
 task_stack_page include/linux/sched/task_stack.h:23 [inline]
 last_frame arch/x86/kernel/unwind_frame.c:82 [inline]
 is_last_frame arch/x86/kernel/unwind_frame.c:87 [inline]
 is_last_task_frame+0x5d/0x370 arch/x86/kernel/unwind_frame.c:156
 unwind_next_frame+0x60/0x350 arch/x86/kernel/unwind_frame.c:276
 __unwind_start+0x3bf/0x530 arch/x86/kernel/unwind_frame.c:417
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xfc/0x280 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xc2/0x100 kernel/stacktrace.c:122
 kmsan_save_stack_with_flags mm/kmsan/core.c:73 [inline]
 kmsan_internal_poison_memory+0x4a/0x90 mm/kmsan/core.c:57
 kmsan_slab_alloc+0xdc/0x160 mm/kmsan/hooks.c:66
 slab_post_alloc_hook mm/slub.c:4508 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x37b/0x1270 mm/slub.c:4837
 mempool_alloc_slab+0x36/0x50 mm/mempool.c:723
 mempool_alloc_noprof+0x19d/0x3c0 mm/mempool.c:567
 bvec_alloc block/bio.c:210 [inline]
 bio_alloc_bioset+0xe1c/0x1a10 block/bio.c:613
 bio_alloc include/linux/bio.h:368 [inline]
 io_submit_init_bio fs/ext4/page-io.c:427 [inline]
 io_submit_add_bh fs/ext4/page-io.c:449 [inline]
 ext4_bio_write_folio+0x1aa8/0x32a0 fs/ext4/page-io.c:590
 mpage_submit_folio+0x399/0x3d0 fs/ext4/inode.c:2080
 mpage_process_page_bufs+0xaef/0xf50 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x175d/0x2660 fs/ext4/inode.c:2730
 ext4_do_writepages+0x11a0/0x7950 fs/ext4/inode.c:2871
 ext4_writepages+0x337/0x870 fs/ext4/inode.c:3019
 do_writepages+0x3f2/0x860 mm/page-writeback.c:2554
 __writeback_single_inode+0xfc/0x1440 fs/fs-writeback.c:1750
 writeback_sb_inodes+0xb52/0x1f40 fs/fs-writeback.c:2041
 __writeback_inodes_wb+0x14e/0x480 fs/fs-writeback.c:2118
 wb_writeback+0x51d/0xcd0 fs/fs-writeback.c:2229
 wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
 wb_do_writeback fs/fs-writeback.c:2386 [inline]
 wb_workfn+0x1125/0x19b0 fs/fs-writeback.c:2414
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb21/0x1e30 kernel/workqueue.c:3358
 worker_thread+0xede/0x1580 kernel/workqueue.c:3439
 kthread+0x53f/0x600 kernel/kthread.c:467
 ret_from_fork+0x20f/0x910 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Local variable reuse.i created at:
 mas_wr_node_store lib/maple_tree.c:3495 [inline]
 mas_wr_store_entry+0x14bd/0x96d0 lib/maple_tree.c:3764
 mas_store_prealloc+0x1834/0x1e60 lib/maple_tree.c:5169

CPU: 0 UID: 0 PID: 83 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: writeback wb_workfn (flush-8:0)
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