check --mode=lowmem loops on fuzzed image bko-155621-bad-block-group-offset

[kdave]

In original mode check works

--mode=original

[1/7] checking root items
[2/7] checking extents
corrupt extent record: key [131072,169,4096]
corrupt extent record: key [4194304,169,4096]
corrupt extent record: key [4198400,169,4096]
corrupt extent record: key [4202496,169,4096]
corrupt extent record: key [4227072,169,4096]
corrupt extent record: key [4231168,169,4096]
corrupt extent record: key [4235264,169,4096]
Chunk[256, 228, 0]: length(4194304), offset(0), type(2) is not found in block group
Chunk[256, 228, 4194304]: length(1638400), offset(4194304), type(5) mismatch with block group[4194304, 192, 1638400]: offset(1638400), objectid(4194304), flags(21474836480)
Chunk[256, 228, 5832704]: length(1638400), offset(5832704), type(5) mismatch with block group[5832704, 192, 1638400]: offset(1638400), objectid(5832704), flags(21474836480)
Block group[0, 0] (flags = 8589934592) didn't find the relative chunk.
Block group[4194304, 1638400] (flags = 21474836480) didn't find the relative chunk.
Block group[5832704, 1638400] (flags = 21474836480) didn't find the relative chunk.
ref mismatch on [131072 4096] extent item 4294967296, found 1
tree extent[131072, 4096] root 3 has no backref item in extent tree
backpointer mismatch on [131072 4096]
bad extent [131072, 135168), type mismatch with chunk
ERROR: invalid generation for extent 4194304, have 17179869184 expect (0, 6]
ref mismatch on [4194304 4096] extent item 4294967296, found 1
tree extent[4194304, 4096] root 5 has no backref item in extent tree
backpointer mismatch on [4194304 4096]
bad extent [4194304, 4198400), type mismatch with chunk
ref mismatch on [4198400 4096] extent item 4294967296, found 1
tree extent[4198400, 4096] root 1 has no backref item in extent tree
backpointer mismatch on [4198400 4096]
bad extent [4198400, 4202496), type mismatch with chunk
ref mismatch on [4202496 4096] extent item 4294967296, found 1
tree extent[4202496, 4096] root 2 has no backref item in extent tree
backpointer mismatch on [4202496 4096]
bad extent [4202496, 4206592), type mismatch with chunk
ERROR: invalid generation for extent 4227072, have 17179869184 expect (0, 6]
ref mismatch on [4227072 4096] extent item 4294967296, found 1
tree extent[4227072, 4096] root 4 has no backref item in extent tree
backpointer mismatch on [4227072 4096]
bad extent [4227072, 4231168), type mismatch with chunk
ERROR: invalid generation for extent 4231168, have 17179869184 expect (0, 6]
ref mismatch on [4231168 4096] extent item 8589934591, found 1
tree extent[4231168, 4096] root 7 has no backref item in extent tree
backpointer mismatch on [4231168 4096]
bad extent [4231168, 4235264), type mismatch with chunk
ERROR: invalid generation for extent 4235264, have 17179869184 expect (0, 6]
ref mismatch on [4235264 4096] extent item 4294967296, found 0
owner ref check failed [4235264 4096]
bad extent [4235264, 4239360), type mismatch with chunk
ERROR: errors found in extent allocation tree or chunk allocation
[3/7] checking free space cache
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
Opening filesystem to check...
Checking filesystem on bko-155621-bad-block-group-offset.raw.restored
UUID: 5cb33553-6f6d-4ce8-83fd-20af5a2f8181
found 28672 bytes used, error(s) found
total csum bytes: 0
total tree bytes: 24576
total fs tree bytes: 4096
total extent tree bytes: 4096
btree space waste bytes: 19892
file data blocks allocated: 0
referenced 0

In --mode=lowmem it loops up to versions 6.5 at least and on 6.1 it crashes:

loop

[1/7] checking root items
[2/7] checking extents
kernel-shared/backref.c:653: __add_inline_refs: Warning: assertion 1 failed, value 1
btrfs(+0xf3e8e)[0x557b017d7e8e]
btrfs(+0xf4806)[0x557b017d8806]
btrfs(+0xd2d2a)[0x557b017b6d2a]
btrfs(+0xdf688)[0x557b017c3688]
btrfs(check_chunks_and_extents_lowmem+0x4e)[0x557b017c787e]
btrfs(+0xb5c69)[0x557b01799c69]
btrfs(main+0x8f)[0x557b01700f9f]
/lib64/libc.so.6(+0x2a1f0)[0x7f2cd2e2a1f0]
/lib64/libc.so.6(__libc_start_main+0x8b)[0x7f2cd2e2a2b9]
btrfs(_start+0x27)[0x557b017024f5]
kernel-shared/backref.c:653: __add_inline_refs: Warning: assertion 1 failed, value 1
btrfs(+0xf3e8e)[0x557b017d7e8e]
btrfs(+0xf4806)[0x557b017d8806]
btrfs(+0xd2d2a)[0x557b017b6d2a]
btrfs(+0xdf688)[0x557b017c3688]
btrfs(check_chunks_and_extents_lowmem+0x4e)[0x557b017c787e]
btrfs(+0xb5c69)[0x557b01799c69]
btrfs(main+0x8f)[0x557b01700f9f]
/lib64/libc.so.6(+0x2a1f0)[0x7f2cd2e2a1f0]
/lib64/libc.so.6(__libc_start_main+0x8b)[0x7f2cd2e2a2b9]
btrfs(_start+0x27)[0x557b017024f5]
kernel-shared/backref.c:653: __add_inline_refs: Warning: assertion 1 failed, value 1
btrfs(+0xf3e8e)[0x557b017d7e8e]
btrfs(+0xf4806)[0x557b017d8806]
btrfs(+0xd2d2a)[0x557b017b6d2a]
btrfs(+0xdf688)[0x557b017c3688]
btrfs(check_chunks_and_extents_lowmem+0x4e)[0x557b017c787e]
btrfs(+0xb5c69)[0x557b01799c69]
btrfs(main+0x8f)[0x557b01700f9f]
/lib64/libc.so.6(+0x2a1f0)[0x7f2cd2e2a1f0]
/lib64/libc.so.6(__libc_start_main+0x8b)[0x7f2cd2e2a2b9]
btrfs(_start+0x27)[0x557b017024f5]
...