=====================================================
BUG: KMSAN: uninit-value in LZ4_decompress_generic lib/lz4/lz4_decompress.c:147 [inline]
BUG: KMSAN: uninit-value in LZ4_decompress_safe_partial+0x94a/0x2190 lib/lz4/lz4_decompress.c:472
 LZ4_decompress_generic lib/lz4/lz4_decompress.c:147 [inline]
 LZ4_decompress_safe_partial+0x94a/0x2190 lib/lz4/lz4_decompress.c:472
 __bio_uncompress+0x62a/0xde0 fs/bcachefs/compress.c:200
 bch2_bio_uncompress+0x523/0x880 fs/bcachefs/compress.c:323
 __bch2_read_endio+0x18de/0x2340 fs/bcachefs/io_read.c:790
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 __alloc_frozen_pages_noprof+0x689/0xf00 mm/page_alloc.c:4993
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2301
 alloc_frozen_pages_noprof mm/mempolicy.c:2372 [inline]
 alloc_pages_noprof+0x102/0x280 mm/mempolicy.c:2392
 __bio_alloc_page_pool fs/bcachefs/io_write.c:119 [inline]
 bch2_bio_alloc_pages_pool+0x8f/0x230 fs/bcachefs/io_write.c:140
 __bch2_read_extent+0x3451/0x60a0 fs/bcachefs/io_read.c:1096
 bch2_read_extent fs/bcachefs/io_read.h:140 [inline]
 bchfs_read+0x3afd/0x4690 fs/bcachefs/fs-io-buffered.c:226
 bch2_readahead+0x1579/0x1c10 fs/bcachefs/fs-io-buffered.c:316
 read_pages+0x159/0xe40 mm/readahead.c:160
 page_cache_ra_order+0xeab/0x14f0 mm/readahead.c:515
 page_cache_sync_ra+0x108a/0x13e0 mm/readahead.c:621
 filemap_get_pages+0xfb3/0x3a70 mm/filemap.c:2591
 filemap_read+0x5c6/0x2190 mm/filemap.c:2702
 bch2_read_iter+0x559/0x21c0 fs/bcachefs/fs-io-direct.c:221
 __kernel_read+0x750/0xda0 fs/read_write.c:528
 kernel_read+0xcb/0x100 fs/read_write.c:546
 prepare_binprm fs/exec.c:1717 [inline]
 search_binary_handler fs/exec.c:1764 [inline]
 exec_binprm fs/exec.c:1810 [inline]
 bprm_execve+0x987/0x18f0 fs/exec.c:1862
 do_execveat_common+0xcaa/0xdf0 fs/exec.c:1968
 do_execve fs/exec.c:2042 [inline]
 __do_sys_execve fs/exec.c:2118 [inline]
 __se_sys_execve fs/exec.c:2113 [inline]
 __x64_sys_execve+0xea/0x130 fs/exec.c:2113
 x64_sys_call+0x1789/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:60
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound __bch2_read_endio
=====================================================