* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [220514 16:50]: > On Sat, 14 May 2022 13:18:26 -0700 syzbot <syzbot+ee1fdd8dcc770a3a169a@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > syzbot has found a reproducer for the following issue on: > > > > HEAD commit: 1e1b28b936ae Add linux-next specific files for 20220513 > > git tree: linux-next > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=11da21b9f00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=e4eb3c0c4b289571 > > dashboard link: https://syzkaller.appspot.com/bug?extid=ee1fdd8dcc770a3a169a > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142757f1f00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17cf0966f00000 > > Thanks. > > So it was there on April 28 and it's there now. Liam, do you think > anything in the mapletree changes could have perturbed the interval > tree handling? It is certainly possible, these two trees are intertwined so much. One area that sticks out as a possibility is vma_expand(). I created a vma_expand() function to handle growing a vma and potentially removing the next vma. I do some interval tree modifications in there. I'll add it to my list of items to look at. > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+ee1fdd8dcc770a3a169a@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN > > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > > CPU: 1 PID: 3612 Comm: syz-executor255 Not tainted 5.18.0-rc6-next-20220513-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > RIP: 0010:____rb_erase_color lib/rbtree.c:354 [inline] > > RIP: 0010:__rb_erase_color+0x159/0xdb0 lib/rbtree.c:413 > > Code: 89 ed 48 89 c5 e9 f5 fe ff ff 4c 8d 45 10 4c 89 c0 48 c1 e8 03 80 3c 18 00 0f 85 3a 08 00 00 4c 8b 65 10 4c 89 e0 48 c1 e8 03 <80> 3c 18 00 0f 85 6a 08 00 00 49 8b 04 24 49 8d 7c 24 08 48 89 f9 > > RSP: 0018:ffffc90002e877a8 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 > > RDX: ffffed100e8d3aed RSI: ffff88807469d768 RDI: ffff8880202132b0 > > RBP: ffff8880202132b0 R08: ffff8880202132c0 R09: ffff88807469d75f > > R10: ffffffff81b02518 R11: 0000000000000001 R12: 0000000000000000 > > R13: 0000000000000000 R14: ffff88807469d768 R15: ffffffff81b01300 > > FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007ffe92002ff8 CR3: 00000000764a0000 CR4: 00000000003506e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <TASK> > > rb_erase_augmented include/linux/rbtree_augmented.h:305 [inline] > > rb_erase_augmented_cached include/linux/rbtree_augmented.h:314 [inline] > > vma_interval_tree_remove+0x694/0xed0 mm/interval_tree.c:23 > > __remove_shared_vm_struct mm/mmap.c:160 [inline] > > unlink_file_vma+0xbd/0x110 mm/mmap.c:175 > > free_pgtables+0x255/0x420 mm/memory.c:440 > > exit_mmap+0x1ff/0x740 mm/mmap.c:3219 > > __mmput+0x128/0x4c0 kernel/fork.c:1180 > > mmput+0x5c/0x70 kernel/fork.c:1201 > > exit_mm kernel/exit.c:510 [inline] > > do_exit+0xa18/0x2a00 kernel/exit.c:782 > > do_group_exit+0xd2/0x2f0 kernel/exit.c:925 > > get_signal+0x2542/0x2600 kernel/signal.c:2857 > > arch_do_signal_or_restart+0x82/0x20f0 arch/x86/kernel/signal.c:869 > > exit_to_user_mode_loop kernel/entry/common.c:166 [inline] > > exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 > > irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:307 > > exc_page_fault+0xc6/0x180 arch/x86/mm/fault.c:1543 > > asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:570 > > RIP: 0033:0x7f1771dc98cf > > Code: Unable to access opcode bytes at RIP 0x7f1771dc98a5. > > RSP: 002b:00007ffe920035a0 EFLAGS: 00010206 > > RAX: 0000000000000001 RBX: 00007f1771e78138 RCX: 0000000000000001 > > RDX: 0000000000000001 RSI: 00007f1771e78138 RDI: 000000000000000b > > RBP: 000000000000000b R08: 0000000000000005 R09: 0000000000000000 > > R10: 0000000000008011 R11: 0000000000000206 R12: 0000000000000000 > > R13: 0000000000000001 R14: 00000000000c3ec0 R15: 0000000000000001 > > </TASK> > > Modules linked in: > > ---[ end trace 0000000000000000 ]--- > > RIP: 0010:____rb_erase_color lib/rbtree.c:354 [inline] > > RIP: 0010:__rb_erase_color+0x159/0xdb0 lib/rbtree.c:413 > > Code: 89 ed 48 89 c5 e9 f5 fe ff ff 4c 8d 45 10 4c 89 c0 48 c1 e8 03 80 3c 18 00 0f 85 3a 08 00 00 4c 8b 65 10 4c 89 e0 48 c1 e8 03 <80> 3c 18 00 0f 85 6a 08 00 00 49 8b 04 24 49 8d 7c 24 08 48 89 f9 > > RSP: 0018:ffffc90002e877a8 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 > > RDX: ffffed100e8d3aed RSI: ffff88807469d768 RDI: ffff8880202132b0 > > RBP: ffff8880202132b0 R08: ffff8880202132c0 R09: ffff88807469d75f > > R10: ffffffff81b02518 R11: 0000000000000001 R12: 0000000000000000 > > R13: 0000000000000000 R14: ffff88807469d768 R15: ffffffff81b01300 > > FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000000c3ec8 CR3: 0000000023516000 CR4: 00000000003506f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > ---------------- > > Code disassembly (best guess): > > 0: 89 ed mov %ebp,%ebp > > 2: 48 89 c5 mov %rax,%rbp > > 5: e9 f5 fe ff ff jmpq 0xfffffeff > > a: 4c 8d 45 10 lea 0x10(%rbp),%r8 > > e: 4c 89 c0 mov %r8,%rax > > 11: 48 c1 e8 03 shr $0x3,%rax > > 15: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) > > 19: 0f 85 3a 08 00 00 jne 0x859 > > 1f: 4c 8b 65 10 mov 0x10(%rbp),%r12 > > 23: 4c 89 e0 mov %r12,%rax > > 26: 48 c1 e8 03 shr $0x3,%rax > > * 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction > > 2e: 0f 85 6a 08 00 00 jne 0x89e > > 34: 49 8b 04 24 mov (%r12),%rax > > 38: 49 8d 7c 24 08 lea 0x8(%r12),%rdi > > 3d: 48 89 f9 mov %rdi,%rcx > >
