Bug#1042546: tac: /tmp/tac...: read error: Illegal seek
On 30/07/2023 20:30, наб wrote:
On Sun, Jul 30, 2023 at 12:14:10PM +0100, Pádraig Brady wrote:
On 30/07/2023 05:09, наб wrote:
$ truncate -s 5G 5G
$ cat 5G | /bin/tac | wc -c
/bin/tac: /tmp/tacOOOwnf: read error: Illegal seek
0
Couldn't repo with 64 bit tac 9.1
Tested on amd64.
or 32 bit tac latest
I just get the expected:
$ cat 5G | git/coreutils/src/tac | wc -c
git/coreutils/src/tac: /tmp/cutmpZRrn27: write error: No space left on device
Well, what if you let /tmp grow enough to allocate the 5G
(or put it on a compressed filesystem that'll discard the zeroes)?
I ran this on a big system so my /tmp has 47G avail,
but I can reproduce your lack of reproduction by making it too small:
# mount -t tmpfs -o size=1g tmpfs dir
$ cat 5G | TMPDIR=dir /bin/tac | wc -c
/bin/tac: dir/tacbIeNII: write error: No space left on device
0
Indeed.
I'm addressing this upstream with the attached.
cheers,
Pádraig
From ef60e3727ee4e4e5c3232a2f44a4f8ef9681aaba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?=
Date: Mon, 31 Jul 2023 12:41:26 +0100
Subject: [PATCH] tac: handle short reads on input
This can be reproduced by getting the read() above 2G,
which induces a short read, thus triggering the erroneous failure.
$ truncate -s 5G 5G
$ cat 5G | TMPDIR=$PWD tac | wc -c
tac: /tmp/tacFt7txA: read error: Illegal seek
0
With the fix in place we now get:
$ cat 5G | TMPDIR=$PWD src/tac | wc -c
5368709120
* src/tac.c (tac_seekable): Use full_read() to handle short reads.
* NEWS: Mention the bug fix.
Reported at https://bugs.debian.org/1042546
---
NEWS | 4
src/tac.c | 3 ++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/NEWS b/NEWS
index 92e591ee2..011058299 100644
--- a/NEWS
+++ b/NEWS
@@ -46,6 +46,10 @@ GNU coreutils NEWS-*- outline -*-
'pr --length=1 --double-space' no longer enters an infinite loop.
[This bug was present in "the beginning".]
+ tac now handles short reads on its input. Previously it may have exited
+ erroneously, especially with large input files with no separators.
+ [This bug was present in "the beginning".]
+
'wc -l' and 'cksum' no longer crash with an "Illegal instruction" error
on x86 Linux kernels that disable XSAVE YMM. This was seen on Xen VMs.
[bug introduced in coreutils-9.0]
diff --git a/src/tac.c b/src/tac.c
index 285f99a74..4c3655895 100644
--- a/src/tac.c
+++ b/src/tac.c
@@ -44,6 +44,7 @@ tac -r -s '.\|
#include
#include "filenamecat.h"
+#include "full-read.h"
#include "safe-read.h"
#include "temp-stream.h"
#include "xbinary-io.h"
@@ -336,7 +337,7 @@ tac_seekable (int input_fd, char const *file, off_t file_pos)
else
match_start = past_end;
- if (safe_read (input_fd, G_buffer, read_size) != read_size)
+ if (full_read (input_fd, G_buffer, read_size) != read_size)
{
error (0, errno, _("%s: read error"), quotef (file));
return false;
--
2.41.0
Bug#1042546: tac: /tmp/tac...: read error: Illegal seek
On Sun, Jul 30, 2023 at 12:14:10PM +0100, Pádraig Brady wrote: > On 30/07/2023 05:09, наб wrote: > > $ truncate -s 5G 5G > > $ cat 5G | /bin/tac | wc -c > > /bin/tac: /tmp/tacOOOwnf: read error: Illegal seek > > 0 > Couldn't repo with 64 bit tac 9.1 Tested on amd64. > or 32 bit tac latest > > I just get the expected: > > $ cat 5G | git/coreutils/src/tac | wc -c > git/coreutils/src/tac: /tmp/cutmpZRrn27: write error: No space left on device Well, what if you let /tmp grow enough to allocate the 5G (or put it on a compressed filesystem that'll discard the zeroes)? I ran this on a big system so my /tmp has 47G avail, but I can reproduce your lack of reproduction by making it too small: # mount -t tmpfs -o size=1g tmpfs dir $ cat 5G | TMPDIR=dir /bin/tac | wc -c /bin/tac: dir/tacbIeNII: write error: No space left on device 0 Best, наб signature.asc Description: PGP signature
Bug#1042546: tac: /tmp/tac...: read error: Illegal seek
On 30/07/2023 05:09, наб wrote: Package: coreutils Version: 9.1-1 Severity: normal Dear Maintainer, $ truncate -s 5G 5G $ cat 5G | /bin/tac | wc -c /bin/tac: /tmp/tacOOOwnf: read error: Illegal seek 0 наб -- System Information: Debian Release: 12.1 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable-debug'), (500, 'stable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Couldn't repo with 64 bit tac 9.1 or 32 bit tac latest I just get the expected: $ cat 5G | git/coreutils/src/tac | wc -c git/coreutils/src/tac: /tmp/cutmpZRrn27: write error: No space left on device cheers, Pádraig
Bug#1042546: tac: /tmp/tac...: read error: Illegal seek
Package: coreutils Version: 9.1-1 Severity: normal Dear Maintainer, $ truncate -s 5G 5G $ cat 5G | /bin/tac | wc -c /bin/tac: /tmp/tacOOOwnf: read error: Illegal seek 0 наб -- System Information: Debian Release: 12.1 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable-debug'), (500, 'stable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 6.1.0-9-amd64 (SMP w/24 CPU threads; PREEMPT) Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_FIRMWARE_WORKAROUND, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages coreutils depends on: ii libacl1 2.3.1-3 ii libattr1 1:2.5.1-4 ii libc62.36-9+deb12u1 ii libgmp10 2:6.2.1+dfsg1-1.1 ii libselinux1 3.4-1+b6 coreutils recommends no packages. coreutils suggests no packages. -- no debconf information signature.asc Description: PGP signature
