syzbot

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BUG: KMSAN: uninit-value in sw842_decompress+0x11f3/0x1780 lib/842/842_decompress.c:303
 sw842_decompress+0x11f3/0x1780 lib/842/842_decompress.c:303
 crypto842_sdecompress+0x46/0x60 crypto/842.c:53
 scomp_acomp_comp_decomp+0xa49/0x1120 include/crypto/internal/scompress.h:-1
 scomp_acomp_decompress+0x30/0x40 crypto/scompress.c:287
 crypto_acomp_decompress+0x5b4/0xe80 crypto/acompress.c:303
 zswap_decompress+0x729/0x1000 mm/zswap.c:967
 zswap_load+0x262/0x570 mm/zswap.c:1627
 swap_read_folio+0x662/0x3050 mm/page_io.c:637
 swap_cluster_readahead+0xa8c/0xb20 mm/swap_state.c:668
 swapin_readahead+0x217/0x1990 mm/swap_state.c:821
 do_swap_page+0x984/0x99b0 mm/memory.c:4753
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x3034/0x6ee0 mm/memory.c:6580
 do_user_addr_fault+0xfe1/0x2550 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x74/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:618
 rseq_set_ids_get_csaddr+0xb6/0x560 include/linux/rseq_entry.h:356
 rseq_update_usr include/linux/rseq_entry.h:382 [inline]
 rseq_slowpath_update_usr kernel/rseq.c:286 [inline]
 __rseq_handle_slowpath+0x247/0x4c0 kernel/rseq.c:312
 rseq_handle_slowpath include/linux/rseq.h:17 [inline]
 resume_user_mode_work include/linux/resume_user_mode.h:62 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0x228/0x1b70 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x1e1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 sw842_decompress+0x11ec/0x1780 lib/842/842_decompress.c:303
 crypto842_sdecompress+0x46/0x60 crypto/842.c:53
 scomp_acomp_comp_decomp+0xa49/0x1120 include/crypto/internal/scompress.h:-1
 scomp_acomp_decompress+0x30/0x40 crypto/scompress.c:287
 crypto_acomp_decompress+0x5b4/0xe80 crypto/acompress.c:303
 zswap_decompress+0x729/0x1000 mm/zswap.c:967
 zswap_load+0x262/0x570 mm/zswap.c:1627
 swap_read_folio+0x662/0x3050 mm/page_io.c:637
 swap_cluster_readahead+0xa8c/0xb20 mm/swap_state.c:668
 swapin_readahead+0x217/0x1990 mm/swap_state.c:821
 do_swap_page+0x984/0x99b0 mm/memory.c:4753
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x3034/0x6ee0 mm/memory.c:6580
 do_user_addr_fault+0xfe1/0x2550 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x74/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:618

Uninit was stored to memory at:
 next_bits+0xac2/0xda0 lib/842/842_decompress.c:118
 sw842_decompress+0x1a6/0x1780 lib/842/842_decompress.c:297
 crypto842_sdecompress+0x46/0x60 crypto/842.c:53
 scomp_acomp_comp_decomp+0xa49/0x1120 include/crypto/internal/scompress.h:-1
 scomp_acomp_decompress+0x30/0x40 crypto/scompress.c:287
 crypto_acomp_decompress+0x5b4/0xe80 crypto/acompress.c:303
 zswap_decompress+0x729/0x1000 mm/zswap.c:967
 zswap_load+0x262/0x570 mm/zswap.c:1627
 swap_read_folio+0x662/0x3050 mm/page_io.c:637
 swap_cluster_readahead+0xa8c/0xb20 mm/swap_state.c:668
 swapin_readahead+0x217/0x1990 mm/swap_state.c:821
 do_swap_page+0x984/0x99b0 mm/memory.c:4753
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x3034/0x6ee0 mm/memory.c:6580
 do_user_addr_fault+0xfe1/0x2550 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x74/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:618

Uninit was created at:
 __alloc_frozen_pages_noprof+0x421/0xab0 mm/page_alloc.c:5263
 __alloc_pages_noprof+0x41/0xd0 mm/page_alloc.c:5274
 __alloc_pages_node_noprof include/linux/gfp.h:285 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:312 [inline]
 alloc_zpdesc mm/zsmalloc.c:237 [inline]
 alloc_zspage+0x394/0x19f0 mm/zsmalloc.c:984
 zs_malloc+0x79d/0x1250 mm/zsmalloc.c:1300
 zswap_compress mm/zswap.c:909 [inline]
 zswap_store_page mm/zswap.c:1428 [inline]
 zswap_store+0x24a0/0x4a90 mm/zswap.c:1539
 swap_writeout+0x8c1/0x1390 mm/page_io.c:275
 writeout mm/vmscan.c:651 [inline]
 pageout mm/vmscan.c:698 [inline]
 shrink_folio_list+0x59e0/0x7fc0 mm/vmscan.c:1418
 evict_folios+0x999d/0xbf30 mm/vmscan.c:4711
 try_to_shrink_lruvec+0x12b6/0x17e0 mm/vmscan.c:4874
 shrink_one+0x43c/0xbd0 mm/vmscan.c:4919
 shrink_many mm/vmscan.c:4982 [inline]
 lru_gen_shrink_node mm/vmscan.c:5060 [inline]
 shrink_node+0x453a/0x51e0 mm/vmscan.c:6047
 kswapd_shrink_node mm/vmscan.c:6901 [inline]
 balance_pgdat mm/vmscan.c:7084 [inline]
 kswapd+0x2b89/0x4d30 mm/vmscan.c:7354
 kthread+0xd5c/0xf00 kernel/kthread.c:463
 ret_from_fork+0x208/0x710 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

CPU: 0 UID: 0 PID: 6069 Comm: udevd Tainted: G             L      syzkaller #0 PREEMPT(none) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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