[syzbot] [mm?] KMSAN: uninit-value in zswap_rb_insert

[syzbot <syzbot+9c9d60f1b20b22ce218a@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    e33c4963bf53 Merge tag 'nfsd-6.9-5' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=123d5a0f180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=776c05250f36d55c
dashboard link: https://syzkaller.appspot.com/bug?extid=9c9d60f1b20b22ce218a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a10175188ebb/disk-e33c4963.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/abe743417d16/vmlinux-e33c4963.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fb10cccc9909/bzImage-e33c4963.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c9d60f1b20b22ce218a@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in zswap_rb_insert+0x1e9/0x330 mm/zswap.c:842
 zswap_rb_insert+0x1e9/0x330 mm/zswap.c:842
 zswap_store+0x22f2/0x2ca0 mm/zswap.c:1591
 swap_writepage+0x126/0x4c0 mm/page_io.c:198
 pageout mm/vmscan.c:660 [inline]
 shrink_folio_list+0x4a55/0x7910 mm/vmscan.c:1323
 evict_folios+0x9d7f/0xcc20 mm/vmscan.c:4537
 try_to_shrink_lruvec+0x160e/0x1a50 mm/vmscan.c:4733
 shrink_one+0x66f/0xd40 mm/vmscan.c:4772
 shrink_many mm/vmscan.c:4835 [inline]
 lru_gen_shrink_node mm/vmscan.c:4935 [inline]
 shrink_node+0x4856/0x55f0 mm/vmscan.c:5894
 shrink_zones mm/vmscan.c:6152 [inline]
 do_try_to_free_pages+0x820/0x2570 mm/vmscan.c:6214
 try_to_free_pages+0xb7b/0x1820 mm/vmscan.c:6449
 __perform_reclaim mm/page_alloc.c:3774 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:3796 [inline]
 __alloc_pages_slowpath+0x1035/0x31a0 mm/page_alloc.c:4202
 __alloc_pages+0xacf/0xe70 mm/page_alloc.c:4588
 alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
 vma_alloc_folio+0x418/0x680 mm/mempolicy.c:2303
 do_cow_fault mm/memory.c:4918 [inline]
 do_fault mm/memory.c:5026 [inline]
 do_pte_missing mm/memory.c:3880 [inline]
 handle_pte_fault mm/memory.c:5300 [inline]
 __handle_mm_fault mm/memory.c:5441 [inline]
 handle_mm_fault+0x4f2f/0xce00 mm/memory.c:5606
 do_user_addr_fault arch/x86/mm/fault.c:1413 [inline]
 handle_page_fault arch/x86/mm/fault.c:1505 [inline]
 exc_page_fault+0x2a0/0x730 arch/x86/mm/fault.c:1563
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
 rep_stos_alternative+0x40/0x80 arch/x86/lib/clear_page_64.S:92
 load_elf_binary+0x212e/0x4d30 fs/binfmt_elf.c:1132
 search_binary_handler fs/exec.c:1778 [inline]
 exec_binprm fs/exec.c:1820 [inline]
 bprm_execve+0xc57/0x21c0 fs/exec.c:1872
 do_execveat_common+0xceb/0xd70 fs/exec.c:1979
 do_execve fs/exec.c:2053 [inline]
 __do_sys_execve fs/exec.c:2129 [inline]
 __se_sys_execve fs/exec.c:2124 [inline]
 __x64_sys_execve+0xf4/0x130 fs/exec.c:2124
 x64_sys_call+0x1612/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:60
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x2de/0x1400 mm/slub.c:2391
 ___slab_alloc+0x1184/0x33d0 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc_node+0x6ea/0xc50 mm/slub.c:3888
 zswap_entry_cache_alloc mm/zswap.c:874 [inline]
 zswap_store+0xb26/0x2ca0 mm/zswap.c:1535
 swap_writepage+0x126/0x4c0 mm/page_io.c:198
 pageout mm/vmscan.c:660 [inline]
 shrink_folio_list+0x4a55/0x7910 mm/vmscan.c:1323
 evict_folios+0x9d7f/0xcc20 mm/vmscan.c:4537
 try_to_shrink_lruvec+0x160e/0x1a50 mm/vmscan.c:4733
 shrink_one+0x66f/0xd40 mm/vmscan.c:4772
 shrink_many mm/vmscan.c:4835 [inline]
 lru_gen_shrink_node mm/vmscan.c:4935 [inline]
 shrink_node+0x4856/0x55f0 mm/vmscan.c:5894
 shrink_zones mm/vmscan.c:6152 [inline]
 do_try_to_free_pages+0x820/0x2570 mm/vmscan.c:6214
 try_to_free_pages+0xb7b/0x1820 mm/vmscan.c:6449
 __perform_reclaim mm/page_alloc.c:3774 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:3796 [inline]
 __alloc_pages_slowpath+0x1035/0x31a0 mm/page_alloc.c:4202
 __alloc_pages+0xacf/0xe70 mm/page_alloc.c:4588
 alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
 alloc_pages+0x1bf/0x1e0 mm/mempolicy.c:2335
 vm_area_alloc_pages mm/vmalloc.c:3561 [inline]
 __vmalloc_area_node mm/vmalloc.c:3637 [inline]
 __vmalloc_node_range+0x100a/0x28b0 mm/vmalloc.c:3818
 vmalloc_user+0x90/0xb0 mm/vmalloc.c:3972
 kcov_ioctl+0x5d/0x660 kernel/kcov.c:704
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
 x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 PID: 5281 Comm: dhcpcd-run-hook Not tainted 6.9.0-rc5-syzkaller-00053-ge33c4963bf53 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


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