| Message ID | 9ac220a55a540ad22f7cb198856b689079f3e8c6.1743875430.git.fdmanana@suse.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs: fix invalid inode pointer after failure to create reloc inode | expand |
在 2025/4/6 03:21, fdmanana@kernel.org 写道: > From: Filipe Manana <fdmanana@suse.com> > > If we have a failure at create_reloc_inode(), under the 'out' label we > assign an error pointer to the 'inode' variable and then return a weird > pointer because we return the expression "&inode->vfs_inode": > > static noinline_for_stack struct inode *create_reloc_inode( > const struct btrfs_block_group *group) > { > (...) > out: > (...) > if (ret) { > if (inode) > iput(&inode->vfs_inode); > inode = ERR_PTR(ret); > } > return &inode->vfs_inode; > } > > This can make us return a pointer that is not an error pointer and make > the caller proceed as if an error didn't happen and later result in an > invalid memory access when dereferencing the inode pointer. The syzbot > reported such a case with the following stack trace: > > R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000000 R14: 431bde82d7b634db R15: 00007ffc55de5790 > </TASK> > BTRFS info (device loop0): relocating block group 6881280 flags data|metadata > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000045: 0000 [#1] SMP KASAN NOPTI > KASAN: null-ptr-deref in range [0x0000000000000228-0x000000000000022f] > CPU: 0 UID: 0 PID: 5332 Comm: syz-executor215 Not tainted 6.14.0-syzkaller-13423-ga8662bcd2ff1 #0 PREEMPT(full) > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > RIP: 0010:relocate_file_extent_cluster+0xe7/0x1750 fs/btrfs/relocation.c:2971 > Code: 00 74 08 48 89 df e8 f8 36 24 fe 48 89 9c 24 30 01 00 00 4c 89 74 24 28 4d 8b 76 10 49 8d 9e 98 fe ff ff 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 ca 36 24 fe 4c 8b 3b 48 8b 44 24 > RSP: 0018:ffffc9000d3375e0 EFLAGS: 00010203 > RAX: 0000000000000045 RBX: 000000000000022c RCX: ffff888000562440 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880452db000 > RBP: ffffc9000d337870 R08: ffffffff84089251 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 > R13: ffffffff9368a020 R14: 0000000000000394 R15: ffff8880452db000 > FS: 000055558bc7b380(0000) GS:ffff88808c596000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055a7a192e740 CR3: 0000000036e2e000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > relocate_block_group+0xa1e/0xd50 fs/btrfs/relocation.c:3657 > btrfs_relocate_block_group+0x777/0xd80 fs/btrfs/relocation.c:4011 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3511 > __btrfs_balance+0x1a93/0x25e0 fs/btrfs/volumes.c:4292 > btrfs_balance+0xbde/0x10c0 fs/btrfs/volumes.c:4669 > btrfs_ioctl_balance+0x3f5/0x660 fs/btrfs/ioctl.c:3586 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:906 [inline] > __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fb4ef537dd9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1b 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 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffc55de5728 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007ffc55de5750 RCX: 00007fb4ef537dd9 > RDX: 0000200000000440 RSI: 00000000c4009420 RDI: 0000000000000003 > RBP: 0000000000000002 R08: 00007ffc55de54c6 R09: 00007ffc55de5770 > R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000000 R14: 431bde82d7b634db R15: 00007ffc55de5790 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:relocate_file_extent_cluster+0xe7/0x1750 fs/btrfs/relocation.c:2971 > Code: 00 74 08 48 89 df e8 f8 36 24 fe 48 89 9c 24 30 01 00 00 4c 89 74 24 28 4d 8b 76 10 49 8d 9e 98 fe ff ff 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 ca 36 24 fe 4c 8b 3b 48 8b 44 24 > RSP: 0018:ffffc9000d3375e0 EFLAGS: 00010203 > RAX: 0000000000000045 RBX: 000000000000022c RCX: ffff888000562440 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880452db000 > RBP: ffffc9000d337870 R08: ffffffff84089251 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 > R13: ffffffff9368a020 R14: 0000000000000394 R15: ffff8880452db000 > FS: 000055558bc7b380(0000) GS:ffff88808c596000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055a7a192e740 CR3: 0000000036e2e000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 00 74 08 48 add %dh,0x48(%rax,%rcx,1) > 4: 89 df mov %ebx,%edi > 6: e8 f8 36 24 fe call 0xfe243703 > b: 48 89 9c 24 30 01 00 mov %rbx,0x130(%rsp) > 12: 00 > 13: 4c 89 74 24 28 mov %r14,0x28(%rsp) > 18: 4d 8b 76 10 mov 0x10(%r14),%r14 > 1c: 49 8d 9e 98 fe ff ff lea -0x168(%r14),%rbx > 23: 48 89 d8 mov %rbx,%rax > 26: 48 c1 e8 03 shr $0x3,%rax > * 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction > 2f: 74 08 je 0x39 > 31: 48 89 df mov %rbx,%rdi > 34: e8 ca 36 24 fe call 0xfe243703 > 39: 4c 8b 3b mov (%rbx),%r15 > 3c: 48 rex.W > 3d: 8b .byte 0x8b > 3e: 44 rex.R > 3f: 24 .byte 0x24 > > So fix this by returning the error immediately. > > Fixes: 00aad5080c51 ("btrfs: make btrfs_iget() return a btrfs inode instead") > Reported-by: syzbot+7481815bb47ef3e702e2@syzkaller.appspotmail.com > Link: https://lore.kernel.org/linux-btrfs/67f14ee9.050a0220.0a13.023e.GAE@google.com/ > Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > fs/btrfs/relocation.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index 62b69274ec03..4bfc5403cf17 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -3801,7 +3801,7 @@ static noinline_for_stack struct inode *create_reloc_inode( > if (ret) { > if (inode) > iput(&inode->vfs_inode); > - inode = ERR_PTR(ret); > + return ERR_PTR(ret); > } > return &inode->vfs_inode; > }
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 62b69274ec03..4bfc5403cf17 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3801,7 +3801,7 @@ static noinline_for_stack struct inode *create_reloc_inode( if (ret) { if (inode) iput(&inode->vfs_inode); - inode = ERR_PTR(ret); + return ERR_PTR(ret); } return &inode->vfs_inode; }