Bug 15273
| Summary: | Regression in ptrace (Wine) starting with 2.6.33-rc1 | ||
|---|---|---|---|
| Product: | Process Management | Reporter: | Michael Stefaniuc (mstefani) |
| Component: | Other | Assignee: | process_other |
| Status: | CLOSED CODE_FIX | ||
| Severity: | high | CC: | maciej.rutecki, rjw, saulius2 |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| URL: | http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=72f674d203cd230426437cdcf7dd6f681dad8b0d | ||
| Kernel Version: | 2.6.33-rc | Subsystem: | |
| Regression: | Yes | Bisected commit-id: | |
| Bug Depends on: | |||
| Bug Blocks: | 14885 | ||
|
Description
Michael Stefaniuc
2010-02-11 16:21:07 UTC
On 02/11/2010 07:22 PM, Frederic Weisbecker wrote: > Thanks a lot for your report. Is there an easy way to reproduce > this? Yes, the bug is 100% reproducible. Even the "stack overflow" bytes are always constant on my two boxes: 932 bytes on my Atom and 1588 bytes on my Q9450 with a x86_64 kernel. Either grab wine-1.1.38 from http://sourceforge.net/projects/wine/files/Source/ or from git git clone git://source.winehq.org/git/wine.git configure make cd dlls/ntdll/tests/ make exception.ok If you build on an x86_64 machine you'll need a pretty complete 32bit setup too, but configure will let you know. If configure doesn't errors out but produces warnings, those can be safely ignored. It means the dependencies are optional and those aren't needed to reproduce this bug. Oh, there might be an other regression in ptrace too; introduced by a previous patch in this series. While bisecting i had a later test fail, something along the lines of "expected 4 exceptions got 0", but the tests completed. Now the stack corruption mask everything else in the tests; e.g. comment out the first test and one of the next tests will go into an infinite loop printing 3 Wine errors over and over again. On 02/13/2010 06:33 PM, K.Prasad wrote: > Can you be more specific with details - such as what was the desired > action/return value of ptrace that your testcase wanted but did not > happen (after the patch applied)? What is the other regression that > you found as a result of another patch in the hw-breakpoint patch > series? > > I am able to see a user-space stackdump upon a 'make exception.ok', > which isn't easy enough (atleast for me) to narrow down to the purported > ptrace defect. Here is a discussion I had with the Wine maintainer on what that specific test does exactly: <julliard> puk: the test changes the debug regs in the context, which makes the server use ptrace to change the debug regs in the test process <puk> cool <puk> so i basically just do an strace on the server <julliard> then it does a GetContext to verify that they have been set correctly <julliard> yes all the ptrace calls are in the server <puk> and capture what ptrace returns <puk> let me guess GetContext uses ptrace too? <julliard> yes <julliard> if it even gets to that point, it sounded like it was crashing inside the exception handler The wineserver is basically the "kernel space" in Wine. Test setup: ----------- # Start the wineserver and and attach to it wineserver strace -p $wineserver_pid >& strace.out # Run the test cd dlls/ntdll/tests/ make exception.ok Results 2.6.33-rcX: ------------------- ptrace(PTRACE_ATTACH, 18036, 0, 0) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg), 0x42424242) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 4, 0) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 8, 0) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 12, 0) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 24, 0) = 0 ptrace(PTRACE_POKEUSER, 18036, offsetof(struct user, u_debugreg) + 28, 0x155) = -1 EINVAL (Invalid argument) Results 2.6.32: --------------- trace(PTRACE_ATTACH, 3077, 0, 0) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg), 0x42424242) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 4, 0) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 8, 0) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 12, 0) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 24, 0) = 0 ptrace(PTRACE_POKEUSER, 3077, offsetof(struct user, u_debugreg) + 28, 0x155) = 0 So it looks like something in the setting of DR7 is broken or at least changed behavior. The function in Wine that does those calls is set_thread_context() from server/ptrace.c. On Wednesday 17 February 2010, Frederic Weisbecker wrote:
> On Mon, Feb 15, 2010 at 12:38:35AM +0100, Rafael J. Wysocki wrote:
> > This message has been generated automatically as a part of a summary report
> > of recent regressions.
> >
> > The following bug entry is on the current list of known regressions
> > from 2.6.32. Please verify if it still should be listed and let the
> tracking team
> > know (either way).
> >
> >
> > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=15273
> > Subject : Regression in ptrace (Wine) starting with 2.6.33-rc1
> > Submitter : Michael Stefaniuc <mstefani@redhat.com>
> > Date : 2010-02-11 16:21 (4 days old)
>
>
> We are taking care of it. It's actually two regressions.
> One has a fix that seems to work, and I'm working on the other one,
> trying to get that upstream before 2.6.33 gets released.
>
> Please keep the ticket open for now.
Handled-By : Frederic Weisbecker <fweisbec@gmail.com> Patch : http://patchwork.kernel.org/patch/80783/ Patch : http://patchwork.kernel.org/patch/80785/ |