https://bugs.kde.org/show_bug.cgi?id=451837
Bug ID: 451837
Summary: When profiling this specific executable, valgrind
fails to break down 0x62 0xF1 0x7F 0x28 0x7F 0x2 0xF
0x87 0x95 0xA1 into 2 separate instructions
Product: valgrind
Version: 3.19 GIT
Platform: Fedora RPMs
OS: Linux
Status: REPORTED
Severity: crash
Priority: NOR
Component: callgrind
Assignee: josef.weidendor...@gmx.de
Reporter: ytr...@sdf-eu.org
Target Milestone: ---
Created attachment 147688
--> https://bugs.kde.org/attachment.cgi?id=147688&action=edit
Attached executable for reproducing the bug.
I built the latest btrfsprogs on my system with profile feedback
(-fprofile-use), the program runs normally on my cpu but when I try to perform
[liveuser@localhost-live btrfs-progs-v5.16.2]$ valgrind --tool=callgrind
--dump-instr=yes --branch-sim=yes --collect-jumps=yes ./btrfs.static check -p
--init-csum-tree /tmp/newly_btrfs_volume_example_with_sha256
with the executable attached, it fails with :
Starting repair.
Opening filesystem to check...
vex amd64->IR: unhandled instruction bytes: 0x62 0xF1 0x7F 0x28 0x7F 0x2 0xF
0x87 0x95 0xA1
vex amd64->IR: REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0
vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE
vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0
==63828== valgrind: Unrecognised instruction at address 0x45dade.
==63828== at 0x45DADE: btrfs_csum_data.constprop.0.isra.0 (disk-io.c:147)
==63828== by 0x45D949: btrfs_check_super (disk-io.c:1666)
==63828== by 0x45D876: btrfs_read_dev_super (disk-io.c:1879)
==63828== by 0x45D5A9: btrfs_scan_one_device (volumes.c:548)
==63828== by 0x45D4E3: check_mounted_where.constprop.0 (open-utils.c:61)
==63828== by 0x45D489: check_mounted (open-utils.c:130)
==63828== by 0x45CD93: cmd_check (main.c:10455)
==63828== by 0x45C6DD: main (commands.h:125)
==63828== Your program just tried to execute an instruction that Valgrind
==63828== did not recognise. There are two possible reasons for this.
==63828== 1. Your program has a bug and erroneously jumped to a non-code
==63828== location. If you are running Memcheck and you just saw a
==63828== warning about a bad jump, it's probably your program's fault.
==63828== 2. The instruction is legitimate but Valgrind doesn't handle it,
==63828== i.e. it's Valgrind's fault. If you think this is the case or
==63828== you are not sure, please let us know and we'll try to fix it.
==63828== Either way, Valgrind will now raise a SIGILL signal which will
==63828== probably kill your program.
==63828==
==63828== Process terminating with default action of signal 4 (SIGILL): dumping
core
==63828== Illegal opcode at address 0x45DADE
==63828== at 0x45DADE: btrfs_csum_data.constprop.0.isra.0 (disk-io.c:147)
==63828== by 0x45D949: btrfs_check_super (disk-io.c:1666)
==63828== by 0x45D876: btrfs_read_dev_super (disk-io.c:1879)
==63828== by 0x45D5A9: btrfs_scan_one_device (volumes.c:548)
==63828== by 0x45D4E3: check_mounted_where.constprop.0 (open-utils.c:61)
==63828== by 0x45D489: check_mounted (open-utils.c:130)
==63828== by 0x45CD93: cmd_check (main.c:10455)
==63828== by 0x45C6DD: main (commands.h:125)
==63828==
==63828== Events : Ir Bc Bcm Bi Bim
==63828== Collected : 791898 132272 8055 1806 620
==63828==
==63828== I refs: 791,898
==63828==
==63828== Branches: 134,078 (132,272 cond + 1,806 ind)
==63828== Mispredicts: 8,675 ( 8,055 cond + 620 ind)
==63828== Mispred rate: 6.5% ( 6.1% + 34.3% )
But unlike what valgrind says 0x62 0xF1 0x7F 0x28 0x7F 0x2 0xF 0x87 0x95 0xA1
consists of 2 instructions instead of 1 and thus in reality isn’t a single
invalid instruction but :
000000000045dac0 <btrfs_csum_data.constprop.0.isra.0>:
45dade: 62 f1 7f 28 7f 02 vmovdqu8 YMMWORD PTR [rdx],ymm0
45dae4: 0f 87 95 a1 fa ff ja 407c7f
<btrfs_csum_data.constprop.0.isra.0.cold+0x19>
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 37. Rpms executables only
Please fix this !
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