From: Chris L. <ch...@ex...> - 2005-03-23 00:00:02
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I'm observing strace(1) behaving oddly under recent 2.4.x versions. Under 2.4.27 with uml-patch-2.4.27-1 and strace 4.5.8, we get: # strace /bin/echo execve("/bin/echo", ["/bin/echo"], [/* 13 vars */]) = 0 exit_group(0) = ? which isn't very useful. Under 2.4.26 + uml-patch-2.4.26-3, the output is as normal: # strace /bin/echo execve("/bin/echo", ["/bin/echo"], [/* 13 vars */]) = 0 uname({sys="Linux", node="vs1", ...}) = 0 brk(0) = 0x804c32c # etc. etc. etc. write(1, "\n", 1 ) = 1 munmap(0x40018000, 4096) = 0 exit_group(0) = ? Later versions (e.g. 2.4.29 + uml-patch-2.4.27-1) show the same behaviour as 2.4.27 above. I haven't looked at the -bb patches exhaustively yet but certainly the same problem occurs with uml-2.4.27-bs2-pre6. Even on the kernels where strace is broken, gdb seems to work (at least to the extent of being able to set breakpoints and break on them -- I haven't tested it extensively). Has anyone else observed this and looked into it in more detail? -- ``Because that's where the money is.'' (Willie Sutton, explaining why he robbed banks) |
From: Chris L. <ch...@ex...> - 2005-03-23 11:33:01
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On Tue, Mar 22, 2005 at 11:59:33PM +0000, Chris Lightfoot wrote: > I'm observing strace(1) behaving oddly under recent 2.4.x > versions. Under 2.4.27 with uml-patch-2.4.27-1 and strace > 4.5.8, we get: [...] > Has anyone else observed this and looked into it in more > detail? It looks as if this is a side-effect of SYSEMU support in the guest. Turning it off (patch to always set use_sysemu = 0) fixes things, at least in 2.4.27. I haven't tried this in 2.4.29 yet. -- ``When I am right, I get angry. Churchill gets angry when he's wrong. So we were often angry at each other.'' (Charles De Gaulle) |
From: Blaisorblade <bla...@ya...> - 2005-03-24 02:08:42
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On Wednesday 23 March 2005 12:32, Chris Lightfoot wrote: > On Tue, Mar 22, 2005 at 11:59:33PM +0000, Chris Lightfoot wrote: > > I'm observing strace(1) behaving oddly under recent 2.4.x > > versions. Under 2.4.27 with uml-patch-2.4.27-1 and strace > > 4.5.8, we get: > > [...] > > > Has anyone else observed this and looked into it in more > > detail? > > It looks as if this is a side-effect of SYSEMU support in > the guest. Turning it off (patch to always set use_sysemu > = 0) fixes things, at least in 2.4.27. I haven't tried > this in 2.4.29 yet. Yes, this was also a problem in 2.6 kernels with SYSEMU support - this went away as a side effect of the big global bunch of patches which went in after 2.6.9, reorganizing and fixing a lot of core code (see 2.6.9-bs7 to get a partial idea). For now, it is unlikely all those fixes will be timely backported... they would destabilize the 2.4 tree. -- Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade |