On Mon, Mar 17, 2025 at 10:33:20AM +0800, Chengming Zhou wrote: > On 2025/3/17 08:13, ffhgfv wrote: > > Hello, I found a bug titled " KASAN: use-after-free Read in zswap_store " with modified syzkaller in the Linux6.14-rc5. > > If you fix this issue, please add the following tag to the commit: Reported-by: Jianzhou Zhao <xnxc22xnxc22@xxxxxx>, xingwei lee <xrivendell7@xxxxxxxxx>, Zhizhuo Tang <strforexctzzchange@xxxxxxxxxxx> > > > > I use the same kernel as syzbot instance upstream: 7eb172143d5508b4da468ed59ee857c6e5e01da6 > > kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=da4b04ae798b7ef6 > > compiler: gcc version 11.4.0 > > ------------[ cut here ]----------------------------------------- > > TITLE: KASAN: use-after-free Read in zswap_store > > ================================================================== > > ================================================================== > > BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] > > BUG: KASAN: use-after-free in do_raw_spin_lock+0x285/0x2e0 kernel/locking/spinlock_debug.c:115 > > Read of size 4 at addr ffff88804e78e014 by task kswapd0/98 > > > > CPU: 0 UID: 0 PID: 98 Comm: kswapd0 Not tainted 6.14.0-rc5-dirty #11 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > > Call Trace: > > <task> > > __dump_stack lib/dump_stack.c:94 [inline] > > dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 > > print_address_description mm/kasan/report.c:408 [inline] > > print_report+0xc1/0x630 mm/kasan/report.c:521 > > kasan_report+0x93/0xc0 mm/kasan/report.c:634 > > debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] > > do_raw_spin_lock+0x285/0x2e0 kernel/locking/spinlock_debug.c:115 > > spin_lock include/linux/spinlock.h:351 [inline] > > z3fold_page_lock mm/z3fold.c:223 [inline] > > z3fold_alloc mm/z3fold.c:1060 [inline] > > z3fold_zpool_malloc+0x9b1/0x1410 mm/z3fold.c:1388 > > zswap_compress mm/zswap.c:971 [inline] > > zswap_store_page mm/zswap.c:1462 [inline] > > zswap_store+0xe46/0x41e0 mm/zswap.c:1571 > > swap_writepage+0x3a7/0x1430 mm/page_io.c:278 > > pageout+0x3bf/0xac0 mm/vmscan.c:696 > > shrink_folio_list+0x3509/0x4480 mm/vmscan.c:1402 > > evict_folios+0x849/0x2100 mm/vmscan.c:4660 > > try_to_shrink_lruvec+0x608/0x9b0 mm/vmscan.c:4821 > > shrink_one+0x412/0x7d0 mm/vmscan.c:4866 > > shrink_many mm/vmscan.c:4929 [inline] > > lru_gen_shrink_node mm/vmscan.c:5007 [inline] > > shrink_node+0x2355/0x3c10 mm/vmscan.c:5978 > > kswapd_shrink_node mm/vmscan.c:6807 [inline] > > balance_pgdat+0xa85/0x1740 mm/vmscan.c:6999 > > kswapd+0x4c0/0xbe0 mm/vmscan.c:7264 > > kthread+0x427/0x880 kernel/kthread.c:464 > > ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 > > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > </task> > > > > The buggy address belongs to the physical page: > > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x564c9cd0a pfn:0x4e78e > > flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff) > > raw: 04fff00000000000 ffffea000139e508 ffffea000139e248 0000000000000000 > > raw: 0000000564c9cd0a 0000000000000000 00000000ffffffff 0000000000000000 > > page dumped because: kasan: bad access detected > > page_owner tracks the page as freed > > page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12800(GFP_NOWAIT|__GFP_NORETRY), pid 98, tgid 98 (kswapd0), ts 431124924160, free_ts 431131252025 > > set_page_owner include/linux/page_owner.h:32 [inline] > > post_alloc_hook mm/page_alloc.c:1551 [inline] > > prep_new_page+0x1b0/0x1e0 mm/page_alloc.c:1559 > > get_page_from_freelist+0x19a2/0x3250 mm/page_alloc.c:3477 > > __alloc_frozen_pages_noprof+0x324/0x6b0 mm/page_alloc.c:4739 > > alloc_pages_mpol+0x20a/0x550 mm/mempolicy.c:2270 > > alloc_pages_noprof+0x1c/0x250 mm/mempolicy.c:2361 > > z3fold_alloc mm/z3fold.c:1036 [inline] > > z3fold_zpool_malloc+0x7aa/0x1410 mm/z3fold.c:1388 > > zswap_compress mm/zswap.c:971 [inline] > > zswap_store_page mm/zswap.c:1462 [inline] > > zswap_store+0xe46/0x41e0 mm/zswap.c:1571 > > swap_writepage+0x3a7/0x1430 mm/page_io.c:278 > > pageout+0x3bf/0xac0 mm/vmscan.c:696 > > shrink_folio_list+0x3509/0x4480 mm/vmscan.c:1402 > > evict_folios+0x849/0x2100 mm/vmscan.c:4660 > > try_to_shrink_lruvec+0x608/0x9b0 mm/vmscan.c:4821 > > shrink_one+0x412/0x7d0 mm/vmscan.c:4866 > > shrink_many mm/vmscan.c:4929 [inline] > > lru_gen_shrink_node mm/vmscan.c:5007 [inline] > > shrink_node+0x2355/0x3c10 mm/vmscan.c:5978 > > kswapd_shrink_node mm/vmscan.c:6807 [inline] > > balance_pgdat+0xa85/0x1740 mm/vmscan.c:6999 > > kswapd+0x4c0/0xbe0 mm/vmscan.c:7264 > > page last free pid 38 tgid 38 stack trace: > > It looks like the z3fold doesn't handle the migration correctly? > But it's suggested that we should use zsmalloc as zswap allocator, > and the z3fold/zbud will be deleted. Yeah this code should be gone in v6.15.
