Hi, We found a bug in Linux 6.10 using syzkaller. It is possibly a logic bug. The reprodcuer is https://gist.github.com/freexxxyyy/5f0c95e95e1bc0fb681e504114b61de8 The bug report is: WARNING: CPU: 0 PID: 8053 at include/linux/rwsem.h:203 mmap_assert_write_locked include/linux/mmap_lock.h:70 [inline] WARNING: CPU: 0 PID: 8053 at include/linux/rwsem.h:203 __is_vma_write_locked include/linux/mm.h:714 [inline] WARNING: CPU: 0 PID: 8053 at include/linux/rwsem.h:203 vma_start_write include/linux/mm.h:733 [inline] WARNING: CPU: 0 PID: 8053 at include/linux/rwsem.h:203 free_pgtables+0x4df/0xbb0 mm/memory.c:403 Modules linked in: CPU: 0 PID: 8053 Comm: syz-executor107 Not tainted 6.10.0 #13 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:rwsem_assert_held_write include/linux/rwsem.h:203 [inline] RIP: 0010:mmap_assert_write_locked include/linux/mmap_lock.h:70 [inline] RIP: 0010:__is_vma_write_locked include/linux/mm.h:714 [inline] RIP: 0010:vma_start_write include/linux/mm.h:733 [inline] RIP: 0010:free_pgtables+0x4df/0xbb0 mm/memory.c:403 Code: 04 00 4d 85 e4 0f 84 86 03 00 00 e8 3b 46 b6 ff 4d 89 ee 4d 89 e5 49 bc 00 00 00 00 00 fc ff df e9 86 fd ff ff e8 21 46 b6 ff <0f> 0b e9 b8 fe ff ff 48 c7 c1 6c 91 24 8f 80 e1 07 80 c1 03 38 c1 RSP: 0018:ffffc9000ac7f748 EFLAGS: 00010293 RAX: ffffffff81db0b3f RBX: ffff88801d8cbe98 RCX: ffff888021fa1e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff81db09ea R09: ffffffff8aed5df0 R10: 0000000000000004 R11: ffff888021fa1e00 R12: ffff88802ce66ba0 R13: ffff88801d8cbe88 R14: ffff88802ce66aa8 R15: 1ffff11003b197d1 FS: 0000000000000000(0000) GS:ffff888063a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff0448ce6b0 CR3: 00000000244bc000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> exit_mmap+0x435/0xa20 mm/mmap.c:3352 __mmput+0x114/0x3b0 kernel/fork.c:1346 exit_mm+0x207/0x2e0 kernel/exit.c:567 do_exit+0x996/0x2560 kernel/exit.c:863 do_group_exit+0x1fd/0x2b0 kernel/exit.c:1025 get_signal+0x1697/0x1730 kernel/signal.c:2909 arch_do_signal_or_restart+0x92/0x7f0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x95/0x280 kernel/entry/common.c:218 do_syscall_64+0x8a/0x150 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x67/0x6f RIP: 0033:0x7fb06353406d Code: Unable to access opcode bytes at 0x7fb063534043. RSP: 002b:00007fb0634d10c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000002 RBX: 00007fb0635c92e8 RCX: 00007fb06353406d RDX: 0000000020000080 RSI: 0000000000000001 RDI: 0000000000000004 RBP: 00007fb0635c92e0 R08: 00007fb0634d1640 R09: 0000000000000000 R10: 00007fb0634d1640 R11: 0000000000000246 R12: 00007fb0635c92ec R13: 0000000000000000 R14: 00007fb0634f67c0 R15: 00007fb0634b1000 </TASK> -- Yours sincerely, Xingyu
