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KASAN: use-after-free Read in sysv_new_block

Status: upstream: reported C repro on 2022/12/01 12:49
Labels: fs (incorrect?)
Reported-by: syzbot+eda782c229b243c648e9@syzkaller.appspotmail.com
First crash: 186d, last: 27d

Cause bisection: failed (error log, bisect log)
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] KASAN: use-after-free Read in sysv_new_block 0 (1) 2022/12/01 12:49
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in sysv_new_block sysv C error 4 157d 187d 0/1 upstream: reported C repro on 2022/11/30 03:11
linux-4.14 KASAN: use-after-free Read in sysv_new_block C 1 95d 179d 0/1 upstream: reported C repro on 2022/12/08 01:50
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2023/05/08 15:00 40m bisect fix upstream job log (0) log
2023/03/29 14:31 50m bisect fix upstream job log (0) log
2023/02/27 14:00 28m bisect fix upstream job log (0) log

Sample crash report:
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
==================================================================
BUG: KASAN: use-after-free in sysv_new_block+0x78c/0x960 fs/sysv/balloc.c:113
Read of size 4 at addr ffff888072d2f0c8 by task syz-executor213/5073

CPU: 1 PID: 5073 Comm: syz-executor213 Not tainted 6.3.0-rc4-syzkaller-00161-g62bad54b26db #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:319 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:430
 kasan_report+0x176/0x1b0 mm/kasan/report.c:536
 sysv_new_block+0x78c/0x960 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:134 [inline]
 get_block+0x2fc/0x16a0 fs/sysv/itree.c:251
 __block_write_begin_int+0x548/0x1a50 fs/buffer.c:2034
 __block_write_begin fs/buffer.c:2084 [inline]
 block_write_begin+0x9c/0x1f0 fs/buffer.c:2145
 sysv_write_begin+0x31/0x70 fs/sysv/itree.c:485
 generic_perform_write+0x300/0x5e0 mm/filemap.c:3926
 __generic_file_write_iter+0x17a/0x400 mm/filemap.c:4054
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4086
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7b2/0xbb0 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fa612edfe99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc2160cf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007fa612edfe99
RDX: 00000000fffffd5e RSI: 000000002000ad00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000140 R09: 0000000000000140
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc2160cfc0
R13: 00007ffc2160d0a0 R14: 431bde82d7b634db R15: 00007ffc2160cfa0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001cb4bc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x72d2f
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001cb4c08 ffffea0001cb4b88 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x8(__GFP_MOVABLE), pid 1, tgid 1 (swapper/0), ts 16687348309, free_ts 18019806101
 split_map_pages+0x24a/0x510 mm/compaction.c:97
 isolate_freepages_range+0x480/0x4e0 mm/compaction.c:734
 alloc_contig_range+0x62e/0x9a0 mm/page_alloc.c:9410
 __alloc_contig_pages mm/page_alloc.c:9433 [inline]
 alloc_contig_pages+0x3e8/0x4e0 mm/page_alloc.c:9510
 debug_vm_pgtable_alloc_huge_page+0xb9/0x110 mm/debug_vm_pgtable.c:1090
 init_args+0x836/0xb10 mm/debug_vm_pgtable.c:1273
 debug_vm_pgtable+0xa8/0x490 mm/debug_vm_pgtable.c:1311
 do_one_initcall+0x23d/0x7d0 init/main.c:1310
 do_initcall_level+0x157/0x210 init/main.c:1383
 do_initcalls+0x3f/0x80 init/main.c:1399
 kernel_init_freeable+0x477/0x630 init/main.c:1638
 kernel_init+0x1d/0x2a0 init/main.c:1526
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1454 [inline]
 free_pcp_prepare mm/page_alloc.c:1504 [inline]
 free_unref_page_prepare+0xe2f/0xe70 mm/page_alloc.c:3388
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:3483
 free_contig_range+0x9e/0x150 mm/page_alloc.c:9532
 destroy_args+0x102/0x9a0 mm/debug_vm_pgtable.c:1023
 debug_vm_pgtable+0x405/0x490 mm/debug_vm_pgtable.c:1403
 do_one_initcall+0x23d/0x7d0 init/main.c:1310
 do_initcall_level+0x157/0x210 init/main.c:1383
 do_initcalls+0x3f/0x80 init/main.c:1399
 kernel_init_freeable+0x477/0x630 init/main.c:1638
 kernel_init+0x1d/0x2a0 init/main.c:1526
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Memory state around the buggy address:
 ffff888072d2ef80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072d2f000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888072d2f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888072d2f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072d2f180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Manager Title
2023/03/31 19:23 upstream 62bad54b26db f325deb0 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root KASAN: use-after-free Read in sysv_new_block
2023/03/30 09:34 upstream ffe78bbd5121 f325deb0 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root KASAN: use-after-free Read in sysv_new_block
2022/12/22 02:29 upstream ec34c2b4ec38 4067838e .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-root KASAN: use-after-free Read in sysv_new_block
2022/12/19 02:51 upstream f9ff5644bcc0 05494336 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-root KASAN: use-after-free Read in sysv_new_block
2022/11/30 22:39 upstream 01f856ae6d0c 4c2a66e8 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: use-after-free Read in sysv_new_block
2023/04/08 14:59 upstream aa318c48808c 71147e29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in sysv_new_block
2023/01/27 19:35 upstream 7c46948a6e9c 9dfcf09c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in sysv_new_block
2023/01/10 05:50 upstream 1fe4fd6f5cad 48bc529a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in sysv_new_block
* Struck through repros no longer work on HEAD.