[Crash-utility] [PATCH 1/3] arm64: relax symbol filters
Dave Anderson
anderson at redhat.com
Thu Nov 19 16:18:45 UTC 2015
----- Original Message -----
> We need to pass some absolute symbols through, but the highest bit test
> is filtering all of them out. Remove that, and filter more specifically.
> ---
> arm64.c | 4 ++--
> defs.h | 3 +++
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arm64.c b/arm64.c
> index 5f8e2f6852434..8cfb863d1bfe2 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -305,7 +305,7 @@ arm64_verify_symbol(const char *name, ulong value, char
> type)
> if (!name || !strlen(name))
> return FALSE;
>
> - if (((type == 'A') || (type == 'a')) && (highest_bit_long(value) != 63))
> + if ((type == 'A') && (HAS_SUFFIX(name, ".c") || HAS_SUFFIX(name, ".o")))
> return FALSE;
>
> if ((value == 0) &&
> @@ -315,7 +315,7 @@ arm64_verify_symbol(const char *name, ulong value, char
> type)
> if (STREQ(name, "$d") || STREQ(name, "$x"))
> return FALSE;
>
> - if ((type == 'A') && STRNEQ(name, "__crc_"))
> + if ((type == 'A') && (STRNEQ(name, "__crc_") || STRNEQ(name,
> "__reg_num_")))
> return FALSE;
>
> if (!(machdep->flags & KSYMS_START) && STREQ(name, "idmap_pg_dir"))
> diff --git a/defs.h b/defs.h
> index 7004619017e41..1bcd1b3b177db 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -155,6 +155,9 @@ static inline int string_exists(char *s) { return (s ?
> TRUE : FALSE); }
> (strcmp((char *)(A), (char *)(B)) == 0))
> #define STRNEQ(A, B) (string_exists((char *)A) && string_exists((char
> *)B) && \
> (strncmp((char *)(A), (char *)(B), strlen((char *)(B))) == 0))
> +#define HAS_SUFFIX(s, suffix) (string_exists((char *)s) &&
> string_exists((char *)suffix) && \
> + strlen((char *)s) > strlen((char *)suffix) && \
> + (strcmp((char *)(s) + strlen((char *)s) - strlen((char *)suffix),
> (char *)suffix) == 0))
> #define BZERO(S, N) (memset(S, NULLCHAR, N))
> #define BCOPY(S, D, C) (memcpy(D, S, C))
> #define BNEG(S, N) (memset(S, 0xff, N))
> --
> 2.4.3
Hi Andrew,
Hey, I appreciate the arm/arm64 interest!
Let's start with this patch first...
The "upper-level" symbol table kept by the crash-specific source
code is only concerned with symbols that are kernel virtual addresses.
Accordingly, the absolute symbols are stripped, and the ARM64 symbol
table normally starts like this:
crash> sym -l
fffffe0000080000 (t) .head.text
fffffe0000080000 (T) _text
fffffe0000080000 (t) efi_head
fffffe0000080040 (t) pe_header
fffffe0000080044 (t) coff_header
fffffe0000080058 (t) optional_header
fffffe0000080070 (t) extra_header_fields
fffffe00000800f8 (t) section_table
fffffe0000081000 (T) stext
fffffe0000081024 (t) preserve_boot_args
...
With your patch 1/3 applied, it starts like this:
crash> syms -l
0 (A) _kernel_flags_le
1 (a) __reg_num_x1
1 (a) __reg_num_x1
1 (a) __reg_num_x1
1 (a) __reg_num_x1
1 (a) __reg_num_x1
1 (a) __reg_num_x1
1 (a) __reg_num_x1
2 (a) __reg_num_x2
2 (a) __reg_num_x2
2 (a) __reg_num_x2
2 (a) __reg_num_x2
2 (a) __reg_num_x2
2 (a) __reg_num_x2
2 (a) __reg_num_x2
3 (a) __reg_num_x3
3 (a) __reg_num_x3
3 (a) __reg_num_x3
3 (a) __reg_num_x3
3 (a) __reg_num_x3
3 (a) __reg_num_x3
3 (a) __reg_num_x3
4 (a) __reg_num_x4
4 (a) __reg_num_x4
4 (a) __reg_num_x4
4 (a) __reg_num_x4
4 (a) __reg_num_x4
4 (a) __reg_num_x4
4 (a) __reg_num_x4
5 (a) __reg_num_x5
5 (a) __reg_num_x5
5 (a) __reg_num_x5
5 (a) __reg_num_x5
5 (a) __reg_num_x5
5 (a) __reg_num_x5
5 (a) __reg_num_x5
6 (a) __reg_num_x6
6 (a) __reg_num_x6
6 (a) __reg_num_x6
6 (a) __reg_num_x6
6 (a) __reg_num_x6
6 (a) __reg_num_x6
6 (a) __reg_num_x6
7 (a) __reg_num_x7
7 (a) __reg_num_x7
7 (a) __reg_num_x7
7 (a) __reg_num_x7
7 (a) __reg_num_x7
7 (a) __reg_num_x7
7 (a) __reg_num_x7
8 (a) __reg_num_x8
8 (a) __reg_num_x8
8 (a) __reg_num_x8
8 (a) __reg_num_x8
8 (a) __reg_num_x8
8 (a) __reg_num_x8
8 (a) __reg_num_x8
9 (a) __reg_num_x9
9 (a) __reg_num_x9
9 (a) __reg_num_x9
9 (a) __reg_num_x9
9 (a) __reg_num_x9
9 (a) __reg_num_x9
9 (a) __reg_num_x9
a (a) __reg_num_x10
a (a) __reg_num_x10
a (a) __reg_num_x10
a (a) __reg_num_x10
a (a) __reg_num_x10
a (a) __reg_num_x10
a (a) __reg_num_x10
b (a) __reg_num_x11
b (a) __reg_num_x11
b (a) __reg_num_x11
b (a) __reg_num_x11
b (a) __reg_num_x11
b (a) __reg_num_x11
b (a) __reg_num_x11
c (a) __reg_num_x12
c (a) __reg_num_x12
c (a) __reg_num_x12
c (a) __reg_num_x12
c (a) __reg_num_x12
c (a) __reg_num_x12
c (a) __reg_num_x12
d (a) __reg_num_x13
d (a) __reg_num_x13
d (a) __reg_num_x13
d (a) __reg_num_x13
d (a) __reg_num_x13
d (a) __reg_num_x13
d (a) __reg_num_x13
e (a) __reg_num_x14
e (a) __reg_num_x14
e (a) __reg_num_x14
e (a) __reg_num_x14
e (a) __reg_num_x14
e (a) __reg_num_x14
e (a) __reg_num_x14
f (a) __reg_num_x15
f (a) __reg_num_x15
f (a) __reg_num_x15
f (a) __reg_num_x15
f (a) __reg_num_x15
f (a) __reg_num_x15
f (a) __reg_num_x15
10 (a) __reg_num_x16
10 (a) __reg_num_x16
10 (a) __reg_num_x16
10 (a) __reg_num_x16
10 (a) __reg_num_x16
10 (a) __reg_num_x16
10 (a) __reg_num_x16
11 (a) __reg_num_x17
11 (a) __reg_num_x17
11 (a) __reg_num_x17
11 (a) __reg_num_x17
11 (a) __reg_num_x17
11 (a) __reg_num_x17
11 (a) __reg_num_x17
12 (a) __reg_num_x18
12 (a) __reg_num_x18
12 (a) __reg_num_x18
12 (a) __reg_num_x18
12 (a) __reg_num_x18
12 (a) __reg_num_x18
12 (a) __reg_num_x18
13 (a) __reg_num_x19
13 (a) __reg_num_x19
13 (a) __reg_num_x19
13 (a) __reg_num_x19
13 (a) __reg_num_x19
13 (a) __reg_num_x19
13 (a) __reg_num_x19
14 (a) __reg_num_x20
14 (a) __reg_num_x20
14 (a) __reg_num_x20
14 (a) __reg_num_x20
14 (a) __reg_num_x20
14 (a) __reg_num_x20
14 (a) __reg_num_x20
15 (a) __reg_num_x21
15 (a) __reg_num_x21
15 (a) __reg_num_x21
15 (a) __reg_num_x21
15 (a) __reg_num_x21
15 (a) __reg_num_x21
15 (a) __reg_num_x21
16 (a) __reg_num_x22
16 (a) __reg_num_x22
16 (a) __reg_num_x22
16 (a) __reg_num_x22
16 (a) __reg_num_x22
16 (a) __reg_num_x22
16 (a) __reg_num_x22
17 (a) __reg_num_x23
17 (a) __reg_num_x23
17 (a) __reg_num_x23
17 (a) __reg_num_x23
17 (a) __reg_num_x23
17 (a) __reg_num_x23
17 (a) __reg_num_x23
18 (a) __reg_num_x24
18 (a) __reg_num_x24
18 (a) __reg_num_x24
18 (a) __reg_num_x24
18 (a) __reg_num_x24
18 (a) __reg_num_x24
18 (a) __reg_num_x24
19 (a) __reg_num_x25
19 (a) __reg_num_x25
19 (a) __reg_num_x25
19 (a) __reg_num_x25
19 (a) __reg_num_x25
19 (a) __reg_num_x25
19 (a) __reg_num_x25
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1a (a) __reg_num_x26
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1b (a) __reg_num_x27
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1c (a) __reg_num_x28
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1d (a) __reg_num_x29
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1e (a) __reg_num_x30
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
1f (a) __reg_num_xzr
200 (A) PECOFF_FILE_ALIGNMENT
1000 (A) stext_offset
80000 (A) _kernel_offset_le
1460000 (A) _kernel_size_le
fffffe0000080000 (t) .head.text
fffffe0000080000 (T) _text
fffffe0000080000 (t) efi_head
fffffe0000080040 (t) pe_header
...
But keeping any absolute symbols below ".head.text" screws things up.
Say for example, here's a normal "rd -S" call:
crash> rd -S fffffe035a2f6580 100
fffffe035a2f6580: 0000000000000000 [kmalloc-16384]
fffffe035a2f6590: 0040410000000002 0000000000000000
fffffe035a2f65a0: 0000000000000000 0000000000000001
fffffe035a2f65b0: [task_struct] 0000000000000002
fffffe035a2f65c0: 000000010c4ac06a 0000000100000000
fffffe035a2f65d0: 0000007800000078 0000000000000078
fffffe035a2f65e0: fair_sched_class 0000000000000400
fffffe035a2f65f0: 0000000000400000 0000000000000001
fffffe035a2f6600: 0000000000000000 0000000000000000
fffffe035a2f6610: fffffe03ffec5878 [task_struct]
fffffe035a2f6620: 0000000000000001 000754096e1781d0
fffffe035a2f6630: 0000000157d0df88 000000004c7c03e4
fffffe035a2f6640: 0000000157cffbf4 0000000000000013
fffffe035a2f6650: 0000000000000001 [kmalloc-192]
fffffe035a2f6660: [kmalloc-512] 0000000000000000
fffffe035a2f6670: 000754096e169e3c 0000000000000000
fffffe035a2f6680: 0000000000000000 0000000000000000
fffffe035a2f6690: 0000b9f100000026 0000000000000026
fffffe035a2f66a0: [task_struct] [task_struct]
fffffe035a2f66b0: 0000000000000000 0000000000000000
fffffe035a2f66c0: 000000000000000a 0000000000000000
fffffe035a2f66d0: 0000000000000000 fffffe03ffec5050
fffffe035a2f66e0: 0000000000000000 [kmalloc-1024]
fffffe035a2f66f0: [task_struct] 0000000000000000
fffffe035a2f6700: 0000000000000000 0000000000000000
fffffe035a2f6710: 0000000000000000 0000000000000000
fffffe035a2f6720: 0000000000000000 0000000000000000
fffffe035a2f6730: 0000000000000000 0000000000000000
fffffe035a2f6740: 0000000000000001 0000000000000000
fffffe035a2f6750: [task_struct] 0000000000000000
fffffe035a2f6760: 0000000000000000 0000000000000000
crash>
With your patch applied, it looks like this:
crash> rd -S fffffe035a2f6580 100
fffffe035a2f6580: __reg_num_x1 [kmalloc-16384]
fffffe035a2f6590: _kernel_size_le+18085866743922690 _kernel_flags_le
fffffe035a2f65a0: _kernel_flags_le _kernel_flags_le
fffffe035a2f65b0: [task_struct] __reg_num_x3
fffffe035a2f65c0: _kernel_size_le+4479828301 __reg_num_x1
fffffe035a2f65d0: _kernel_size_le+515374710904 __reg_num_xzr+89
fffffe035a2f65e0: fair_sched_class PECOFF_FILE_ALIGNMENT+512
fffffe035a2f65f0: _kernel_offset_le+3670016 __reg_num_x1
fffffe035a2f6600: _kernel_flags_le _kernel_flags_le
fffffe035a2f6610: [task_struct] [task_struct]
fffffe035a2f6620: _kernel_flags_le _kernel_size_le+2062727142285104
fffffe035a2f6630: _kernel_size_le+5760795604 _kernel_size_le+1409972385
fffffe035a2f6640: _kernel_size_le+5760749924 __reg_num_x20
fffffe035a2f6650: __reg_num_x1 [kmalloc-192]
fffffe035a2f6660: [kmalloc-512] _kernel_flags_le
fffffe035a2f6670: _kernel_size_le+2062727142285104 _kernel_size_le+1945805182
fffffe035a2f6680: _kernel_flags_le _kernel_flags_le
fffffe035a2f6690: _kernel_size_le+204101119508525 __reg_num_xzr+14
fffffe035a2f66a0: [task_struct] [task_struct]
fffffe035a2f66b0: _kernel_flags_le _kernel_flags_le
fffffe035a2f66c0: __reg_num_x10 _kernel_flags_le
fffffe035a2f66d0: _kernel_flags_le fffffe03ffee5050
fffffe035a2f66e0: _kernel_flags_le [kmalloc-1024]
fffffe035a2f66f0: [task_struct] _kernel_flags_le
fffffe035a2f6700: _kernel_flags_le _kernel_flags_le
fffffe035a2f6710: _kernel_flags_le _kernel_flags_le
fffffe035a2f6720: _kernel_flags_le _kernel_flags_le
fffffe035a2f6730: _kernel_flags_le _kernel_flags_le
fffffe035a2f6740: __reg_num_x1 _kernel_flags_le
fffffe035a2f6750: [task_struct] _kernel_flags_le
fffffe035a2f6760: _kernel_flags_le _kernel_flags_le
crash>
As I understand it, you're only interested in the "_kernel_flags_le"
value, so let's just key on that particular absolute symbol in
arm64_verify_symbol(), and stash it aside for later use.
Dave
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