Messages in this thread | | | Subject | Re: Error returns not handled correctly by sysfs.c:subsys_attr_store() | From | Andrew Patterson <> | Date | Thu, 03 Jan 2008 17:56:13 -0700 |
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On Thu, 2008-01-03 at 17:17 -0700, Andrew Patterson wrote: > On Fri, 2008-01-04 at 09:07 +0900, Tejun Heo wrote: > > Hello, > > > > Andrew Patterson wrote: > > > It looks like this is a shell issue. After looking through the sysfs > > > code, I realized that this problem seems to be driven from user-land. > > > So I performed some experiments: > > > > > > 1. Wrote a simple program that just used write(2) to write to the > > > sysfs entry. This works fine. > > > 2. Used /bin/echo instead of the built-in echo command. This too > > > works fine. > > > 3. Tried several shells. Zsh and Bash both fail. Csh works fine. > > > > > > I then ran strace on the following shell-script: > > > > > > #!/bin/bash > > > > > > echo x > allow_restart > > > echo y > allow_restart > > > echo z > allow_restart > > > > > > and got: > > > > > > # strace -e trace=write ~/tmp/tester.sh > > > write(1, "x\n", 2) = -1 EINVAL (Invalid argument) > > > write(1, "x\n", 2) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 4: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\n", 4) = -1 EINVAL (Invalid argument) > > > write(1, "x\ny\n", 4) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 5: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\nz\n", 6) = -1 EINVAL (Invalid argument) > > > write(1, "x\ny\nz\n", 6) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 6: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\nz\n", 6x > > > y > > > z > > > ) = 6 > > > Process 3800 detached > > > > Eeeeeeeekkkk.... That's scary. Which distro are you using and what does > > 'bash --version' say? > > IA64 Debian lenny. > > # bash --version > GNU bash, version 3.1.17(1)-release (ia64-unknown-linux-gnu) > > # zsh --version > zsh 4.3.4 (ia64-unknown-linux-gnu) > > # csh --version > tcsh 6.14.00 (Astron) 2005-03-25 (ia64-unknown-linux) options > wide,nls,dl,al,kan,rh,nd,color,filec > > I suppose I should try this an ia32 box again, and perhaps with some > other distros. I am not sure what the kernel can do about this, but it > might be nice to report it to the shell maintainers.
Some further tests:
AMD running Debian lenny with i686 kernel -- fails. Bash version = 3.1.17(1)
Intel running Ubuntu/gutsy with i686 kernel -- fails. Bash version = 3.2.25(1)
Itanium running SLES10 with ia64 kernel -- succeeds. Bash version = 3.1.17(1)
BTW, I found a way to reproduce this without modifying the kernel. The /sys/class/scsi_host/*/state sysfs store routine returns EINVAL if an invalid state is written. So just echo 2 bad values to the the state sysfs entry while running strace.
Andrew
-- Andrew Patterson Hewlett-Packard Company
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