* Re: [PATCH] Re: Shared memory shmat/dt not working well in
@ 2002-10-01 16:02 Petr Vandrovec
2002-10-01 17:14 ` Hugh Dickins
0 siblings, 1 reply; 5+ messages in thread
From: Petr Vandrovec @ 2002-10-01 16:02 UTC (permalink / raw)
To: Hugh Dickins; +Cc: Andrew Morton, linux-kernel
On 1 Oct 02 at 14:09, Hugh Dickins wrote:
> Exemplary bug report! Many thanks for taking so much trouble to
> reproduce the problem. Patch below (against 2.5.39) should fix it:
> I'll send Linus and Andrew when I can get hold of a 2.5.40 tree.
You are my hero! It fixed dnetc client failing with SIGSEGV after call
to sys_mprotect().
Unfortunately it did not fixed another problem I have with sys_mprotect.
If I start X, system stops to do anything useful. After SAK I could
do remote connect and running 'w' and 'ps axf' moved them to 'D' state.
Clean sysrq-u,s,b was possible. 2.5.40 kernel plus Hugh's patch, 100%
reproducible with 2.5.40 SMP (non-preempt) kernel running on UP here...
Thanks,
Petr Vandrovec
Oct 1 17:47:35 vana kernel: SysRq : SAK
Oct 1 17:47:35 vana kernel: SAK: killed process 1482 (XFree86): fd#3 opened to the tty
...
Oct 1 17:47:55 vana kernel: XFree86 D DADE7A60 0 1482 1481 (NOTLB)
Oct 1 17:47:55 vana kernel: Call Trace:
Oct 1 17:47:55 vana kernel: [<c01167df>]schedule+0x3bb/0x488
Oct 1 17:47:55 vana kernel: [<c019bdd5>]rwsem_down_read_failed+0x165/0x188
Oct 1 17:47:55 vana kernel: [<c0114adb>].text.lock.fault+0x7/0x6c
Oct 1 17:47:55 vana kernel: [<c01146b0>]do_page_fault+0x0/0x424
Oct 1 17:47:55 vana kernel: [<c01323a2>]do_generic_file_read+0xee/0x35c
Oct 1 17:47:55 vana kernel: [<c0132602>]do_generic_file_read+0x34e/0x35c
Oct 1 17:47:55 vana kernel: [<c01328cb>]__generic_file_aio_read+0x187/0x1a0
Oct 1 17:47:55 vana kernel: [<c0132610>]file_read_actor+0x0/0x134
Oct 1 17:47:55 vana kernel: [<c01372bc>]free_block+0x168/0x250
Oct 1 17:47:55 vana kernel: [<c0107ec9>]error_code+0x2d/0x38
Oct 1 17:47:55 vana kernel: [<c011216f>]flush_tlb_mm+0x1b/0x70
Oct 1 17:47:55 vana kernel: [<c0133ed1>]change_protection+0x1a1/0x1dc
Oct 1 17:47:55 vana kernel: [<c01341ed>]mprotect_fixup+0x16d/0x188
Oct 1 17:47:55 vana kernel: [<c0134392>]sys_mprotect+0x18a/0x2c4
Oct 1 17:47:55 vana kernel: [<c0107467>]syscall_call+0x7/0xb
...
Oct 1 17:47:55 vana kernel: w D DADE7A60 0 1563 1558 (NOTLB)
Oct 1 17:47:55 vana kernel: Call Trace:
Oct 1 17:47:55 vana kernel: [<c015be79>]dput+0x19/0x1d4
Oct 1 17:47:55 vana kernel: [<c019bdd5>]rwsem_down_read_failed+0x165/0x188
Oct 1 17:47:55 vana kernel: [<c016fecf>].text.lock.array+0x6d/0x10e
Oct 1 17:47:55 vana kernel: [<c013b238>]__get_free_pages+0x28/0x60
Oct 1 17:47:55 vana kernel: [<c016c807>]proc_info_read+0x4f/0x108
Oct 1 17:47:55 vana kernel: [<c0146580>]vfs_read+0xb4/0x134
Oct 1 17:47:55 vana kernel: [<c014676a>]sys_read+0x2a/0x3c
Oct 1 17:47:55 vana kernel: [<c0107467>]syscall_call+0x7/0xb
...
Oct 1 17:47:55 vana kernel: ps D DADE7A60 0 1583 1582 (NOTLB)
Oct 1 17:47:55 vana kernel: Call Trace:
Oct 1 17:47:55 vana kernel: [<c015be79>]dput+0x19/0x1d4
Oct 1 17:47:55 vana kernel: [<c019bdd5>]rwsem_down_read_failed+0x165/0x188
Oct 1 17:47:55 vana kernel: [<c016fecf>].text.lock.array+0x6d/0x10e
Oct 1 17:47:55 vana kernel: [<c013b238>]__get_free_pages+0x28/0x60
Oct 1 17:47:55 vana kernel: [<c016c807>]proc_info_read+0x4f/0x108
Oct 1 17:47:55 vana kernel: [<c0146580>]vfs_read+0xb4/0x134
Oct 1 17:47:55 vana kernel: [<c014676a>]sys_read+0x2a/0x3c
Oct 1 17:47:55 vana kernel: [<c0107467>]syscall_call+0x7/0xb
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] Re: Shared memory shmat/dt not working well in 2002-10-01 16:02 [PATCH] Re: Shared memory shmat/dt not working well in Petr Vandrovec @ 2002-10-01 17:14 ` Hugh Dickins 2002-10-01 17:56 ` Petr Vandrovec ` (2 more replies) 0 siblings, 3 replies; 5+ messages in thread From: Hugh Dickins @ 2002-10-01 17:14 UTC (permalink / raw) To: Petr Vandrovec; +Cc: Andrew Morton, Christoph Hellwig, linux-kernel On Tue, 1 Oct 2002, Petr Vandrovec wrote: > > You are my hero! Aww, shucks! I guess I'd better have a go at your next problem... > Unfortunately it did not fixed another problem I have with sys_mprotect. > If I start X, system stops to do anything useful. After SAK I could > do remote connect and running 'w' and 'ps axf' moved them to 'D' state. > Oct 1 17:47:55 vana kernel: [<c0107ec9>]error_code+0x2d/0x38 > Oct 1 17:47:55 vana kernel: [<c011216f>]flush_tlb_mm+0x1b/0x70 > Oct 1 17:47:55 vana kernel: [<c0133ed1>]change_protection+0x1a1/0x1dc > Oct 1 17:47:55 vana kernel: [<c01341ed>]mprotect_fixup+0x16d/0x188 Looks to me like flush_tlb_mm is faulting on the vma->vm_mm given it. And looks to me like mprotect_fixup, in the merge case, may be passing an already freed vma to change_protection. I'm not as confident about this patch as the earlier one, but I believe it's correct: please give it a try, and maybe Christoph will confirm or deny it. Hugh --- 2.5.40/mm/mprotect.c Fri Sep 27 23:56:45 2002 +++ linux/mm/mprotect.c Tue Oct 1 18:00:31 2002 @@ -186,8 +186,10 @@ /* * Try to merge with the previous vma. */ - if (mprotect_attempt_merge(vma, *pprev, end, newflags)) + if (mprotect_attempt_merge(vma, *pprev, end, newflags)) { + vma = *pprev; goto success; + } } else { error = split_vma(mm, vma, start, 1); if (error) ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Re: Shared memory shmat/dt not working well in 2002-10-01 17:14 ` Hugh Dickins @ 2002-10-01 17:56 ` Petr Vandrovec 2002-10-01 19:01 ` Christoph Hellwig 2002-10-01 19:15 ` Andrew Morton 2 siblings, 0 replies; 5+ messages in thread From: Petr Vandrovec @ 2002-10-01 17:56 UTC (permalink / raw) To: Hugh Dickins; +Cc: Andrew Morton, Christoph Hellwig, linux-kernel On Tue, Oct 01, 2002 at 06:14:04PM +0100, Hugh Dickins wrote: > On Tue, 1 Oct 2002, Petr Vandrovec wrote: > > > > You are my hero! > > Aww, shucks! I guess I'd better have a go at your next problem... > > Looks to me like flush_tlb_mm is faulting on the vma->vm_mm given it. > And looks to me like mprotect_fixup, in the merge case, may be passing > an already freed vma to change_protection. I'm not as confident about > this patch as the earlier one, but I believe it's correct: please > give it a try, and maybe Christoph will confirm or deny it. Thanks. It fixed my problem (again ;-) ). Maybe I should already asked yesterday instead of starring at mprotect code. Many thanks, Petr Vandrovec vandrove@vc.cvut.cz > Hugh > > --- 2.5.40/mm/mprotect.c Fri Sep 27 23:56:45 2002 > +++ linux/mm/mprotect.c Tue Oct 1 18:00:31 2002 > @@ -186,8 +186,10 @@ > /* > * Try to merge with the previous vma. > */ > - if (mprotect_attempt_merge(vma, *pprev, end, newflags)) > + if (mprotect_attempt_merge(vma, *pprev, end, newflags)) { > + vma = *pprev; > goto success; > + } > } else { > error = split_vma(mm, vma, start, 1); > if (error) > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Re: Shared memory shmat/dt not working well in 2002-10-01 17:14 ` Hugh Dickins 2002-10-01 17:56 ` Petr Vandrovec @ 2002-10-01 19:01 ` Christoph Hellwig 2002-10-01 19:15 ` Andrew Morton 2 siblings, 0 replies; 5+ messages in thread From: Christoph Hellwig @ 2002-10-01 19:01 UTC (permalink / raw) To: Hugh Dickins; +Cc: Petr Vandrovec, Andrew Morton, linux-kernel On Tue, Oct 01, 2002 at 06:14:04PM +0100, Hugh Dickins wrote: > And looks to me like mprotect_fixup, in the merge case, may be passing > an already freed vma to change_protection. I'm not as confident about > this patch as the earlier one, but I believe it's correct: please > give it a try, and maybe Christoph will confirm or deny it. Looks good. My intial patch didn't do the the change_protection at all, and it looks like the fix someone (akpm?) submitted wasn't exactly correct. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Re: Shared memory shmat/dt not working well in 2002-10-01 17:14 ` Hugh Dickins 2002-10-01 17:56 ` Petr Vandrovec 2002-10-01 19:01 ` Christoph Hellwig @ 2002-10-01 19:15 ` Andrew Morton 2 siblings, 0 replies; 5+ messages in thread From: Andrew Morton @ 2002-10-01 19:15 UTC (permalink / raw) To: Hugh Dickins; +Cc: Petr Vandrovec, Christoph Hellwig, linux-kernel Hugh Dickins wrote: > > ... > --- 2.5.40/mm/mprotect.c Fri Sep 27 23:56:45 2002 > +++ linux/mm/mprotect.c Tue Oct 1 18:00:31 2002 > @@ -186,8 +186,10 @@ > /* > * Try to merge with the previous vma. > */ > - if (mprotect_attempt_merge(vma, *pprev, end, newflags)) > + if (mprotect_attempt_merge(vma, *pprev, end, newflags)) { > + vma = *pprev; > goto success; > + } > } else { > error = split_vma(mm, vma, start, 1); > if (error) Got that, thanks. I think that's enough "cleanups" for 2.5, guys. Let's concentrate on missing must-have functionality, bugs and tuning from now. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2002-10-01 19:10 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2002-10-01 16:02 [PATCH] Re: Shared memory shmat/dt not working well in Petr Vandrovec 2002-10-01 17:14 ` Hugh Dickins 2002-10-01 17:56 ` Petr Vandrovec 2002-10-01 19:01 ` Christoph Hellwig 2002-10-01 19:15 ` Andrew Morton
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