2023-08-31 05:32:34

by Andreas Schwab

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Subject: Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible

This breaks booting on ppc32:

Kernel attemptd to writ user page (1ff0) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel data access on write at 0x00001ff0
Faulting instruction address: 0xc0009554
Vector: 300 (Data Access) at [c0b09d10]
pc: c0009554: do_softirq_own_stack+0x18/0x30
lr: c004f480: __irq_exit_rcu+0x70/0xc0
sp: c0b09dd0
msr: 1032
dar: 1ff0
dsisr: 42000000
current = 0xc0a08360
pid = 0, comm = swapper
Linux version 6.5.0 ...
enter ? for help
[c0b09de0] c00ff480 __irq_exit_rcu+0x70/0xc0
[c0b09df0] c0005a98 Decrementer_virt+0x108/0x10c
--- Exception: 900 (Decrementer) at c06cfa0c __schedule+0x4fc/0x510
[c0b09ec0] c06cf75c __schedule+0x1cc/0x510 (unreliable)
[c0b09ef0] c06cfc90 __cond_resched+0x2c/0x54
[c0b09f00] c06d07f8 mutex_lock_killable+0x18/0x5c
[c0b09f10] c013c404 pcpu_alloc+0x110/0x4dc
[c0b09f70] c000cc34 alloc_descr.isra.18+0x48/0x144
[c0b09f90] c0988aa0 early_irq_init+0x64/0x8c
[c0b09fa0] c097a5a4 start_kernel+0x5b4/0x7b0
[c0b09ff0] 00003dc0
mon>

--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."


2023-09-13 00:45:32

by Andreas Schwab

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Subject: Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible

Any news? This is still broken.

--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."

2023-09-13 05:27:07

by Liam R. Howlett

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Subject: Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible

* Andreas Schwab <[email protected]> [230912 14:15]:
> Any news? This is still broken.

I have a proposed fix. I seem to have caused a pre-existing problem to
show up. Please see if the attached works for you, and I'll send it
to a lot of people.

Thanks,
Liam


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0001-init-main-Clear-boot-task-idle-flag.patch (1.57 kB)
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