> 1.
> ==4996== Invalid read of size 4
> ==4996== at 0x40054EC: ??? (in /lib/ld-uClibc-0.9.33.2.so
<http://ld-uClibc-0.9.33.2.so>)
> ==4996== Address 0x7dbb6664 is on thread 1's stack
> ==4996== 20 bytes below stack pointer
GDB:
1.
(gdb) info reg
r0 0x4007148 67137864
r1 0x0 0
r2 0x49ba000 77307904
r3 0x49bd90c 77322508
r4 0x4015f78 67198840
r5 0x4006054 67133524
r6 0xa 10
r7 0x4006ac0 67136192
r8 0x24 36
r9 0x401602c 67199020
r10 0x7dbb6a48 2109434440
r11 0x7dbb6674 2109433460
r12 0x7dbb6678 2109433464
sp 0x7dbb6678 0x7dbb6678
lr 0x40054ec 67130604
pc 0x40054ec 0x40054ec
cpsr 0x20000010 536870928
(gdb) x/9i $pc-4*4
0x40054dc: beq 0x40054ec
0x40054e0: ldr r2, [r7]
0x40054e4: add r3, r3, r2
0x40054e8: blx r3
=> 0x40054ec: mov r0, r7
0x40054f0: bl 0x4001440
0x40054f4: b 0x40054b8
0x40054f8: ldr r1, [r6, #88] ; 0x58
0x40054fc: sub sp, sp, #16
This is strange. None of the instructions (in any of the four cases)
that are designated by the address in "at 0x..." is a memory fetch 'ldr'
which would be necessary to correspond to the complaint "Invalid read of size
4".
However, I see that each of the 4 complaints is immediately after a 'blx'
instruction.
'blx' has a history of problems in both hardware and software.
Exactly what hardware are you running? Please report the output of "lscpu" and "cat
/proc/cpuinfo".
Also, please tell us which Linux distribution, and the exact package name of the
compiled binary package for uClibc, and where anyone can download a copy of the
package
(both compiled binary and source code).
Meanwhile, please invoke with these diagnostic flags:
valgrind --trace-notbelow=0 --trace-flags=10000000 /bin/true 2>vgtrace.txt
The re-directed stderr vgtrace.txt will be an instruction-by-instruction trace
[it will be large, probably about 5 MB or so] where the individual blocks look
like
***** [This example was generated on x86_64.]
==== SB 0 (evchecks 0) [tid 1] 0x4000c50 UNKNOWN_FUNCTION
/usr/lib64/ld-2.24.so+0xc50
------------------------ Front end ------------------------
0x4000C50: movq %rsp,%rdi
------ IMark(0x4000C50, 3, 0) ------
PUT(72) = GET:I64(48)
PUT(184) = 0x4000C53:I64
*****
where the "SB 0" is a serial number of the block. Find the 'blx' instruction
and its enclosing "SB nnnnn". Then look forward until you find the SB for the
pc that is specified in the complaint from memcheck. Select the entire range
of SB
(from the 'blx' to the complaint) into a file, gzip it, and upload it somewhere
that anyone interested can download it. The idea is to find out how memcheck
got the address that it is complaining about.
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