x/mobile: gomobile apps crash inside runtime.usleep() on Android O beta #20409

cjb · 2017-05-18T16:36:54Z

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (`go version`)?

go version go1.8.1 linux/amd64

What operating system and processor architecture are you using (`go env`)?

This is gomobile on Android O -- crashes on both x86 inside the simulator, and on device with arm64 on a Nexus 6P.

What did you do?

If possible, provide a recipe for reproducing the error.
A complete runnable program is good.
A link on play.golang.org is best.

I called runtime.usleep() from Go code. I haven't made a minimal testcase yet, sorry.

What did you expect to see?

A delay.

What did you see instead?

Crashes due to seccomp policy violation. On amd64, in the Android simulator:

05-17 16:43:08.084 18543 18543 F DEBUG   : Build fingerprint: 'Android/sdk_gphone_x86/generic_x86:O/OSR1.170321.002/3834619:userdebug/test-keys'
05-17 16:43:08.084 18543 18543 F DEBUG   : Revision: '0'
05-17 16:43:08.084 18543 18543 F DEBUG   : ABI: 'x86'
05-17 16:43:08.084 18543 18543 F DEBUG   : pid: 18519, tid: 18538, name: ybase.ossifrage  >>> io.keybase.ossifrage <<<
05-17 16:43:08.084 18543 18543 F DEBUG   : signal 31 (SIGSYS), code 1 (SYS_SECCOMP), fault addr --------
05-17 16:43:08.084 18543 18543 F DEBUG   : Cause: seccomp prevented call to disallowed x86 system call 142
05-17 16:43:08.084 18543 18543 F DEBUG   :     eax 0000008e  ebx 00000000  ecx 00000000  edx 00000000
05-17 16:43:08.084 18543 18543 F DEBUG   :     esi 00000000  edi 91e9a77c
05-17 16:43:08.084 18543 18543 F DEBUG   :     xcs 00000073  xds 0000007b  xes 0000007b  xfs 0000003b  xss 0000007b
05-17 16:43:08.084 18543 18543 F DEBUG   :     eip 92342149  ebp 5fa84690  esp 91e9a77c  flags 00000246
05-17 16:43:08.094 18543 18543 F DEBUG   : 
05-17 16:43:08.094 18543 18543 F DEBUG   : backtrace:
05-17 16:43:08.094 18543 18543 F DEBUG   :     #00 pc 002ad149  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.usleep+41)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #01 pc 0028ab6b  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.runqgrab+155)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #02 pc 0028ad30  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.runqsteal+80)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #03 pc 002844ca  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.findrunnable+2346)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #04 pc 00284a2d  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.schedule+573)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #05 pc 00282027  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.mstart1+263)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #06 pc 00281f12  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so (runtime.mstart+82)
05-17 16:43:08.094 18543 18543 F DEBUG   :     #07 pc 010e1db2  /data/app/io.keybase.ossifrage-vN7ak8XPsBIXVVyb4sc7EA==/lib/x86/libgojni.so

On ARM on a Nexus 6P:

05-17 15:27:53.222 15775-15775/? A/DEBUG: Build fingerprint: 'google/angler/angler:O/OPP2.170420.017/3990407:user/release-keys'
05-17 15:27:53.222 15775-15775/? A/DEBUG: Revision: '0'
05-17 15:27:53.222 15775-15775/? A/DEBUG: ABI: 'arm'
05-17 15:27:53.222 15775-15775/? A/DEBUG: pid: 15749, tid: 15769, name: ybase.ossifrage  >>> io.keybase.ossifrage <<<
05-17 15:27:53.222 15775-15775/? A/DEBUG: signal 31 (SIGSYS), code 1 (SYS_SECCOMP), fault addr --------
05-17 15:27:53.222 15775-15775/? A/DEBUG: Cause: seccomp prevented call to disallowed arm system call 142
05-17 15:27:53.223 15775-15775/? A/DEBUG:     r0 00000000  r1 00000000  r2 00000000  r3 00000000
05-17 15:27:53.223 15775-15775/? A/DEBUG:     r4 cea92890  r5 00000000  r6 00000000  r7 0000008e
05-17 15:27:53.223 15775-15775/? A/DEBUG:     r8 00003d85  r9 dfbfeb40  sl 8b0885a0  fp 00002710
05-17 15:27:53.223 15775-15775/? A/DEBUG:     ip ec32f63c  sp cea9288c  lr cee3f8a8  pc cee3f8cc  cpsr 800f0010
05-17 15:27:53.258 15775-15775/? A/DEBUG: backtrace:
05-17 15:27:53.258 15775-15775/? A/DEBUG:     #00 pc 002af8cc  /data/app/io.keybase.ossifrage-ZEUhtPsnVNpH6KCvHYNzEQ==/lib/arm/libgojni.so (runtime.usleep+48)
05-17 15:27:53.258 15775-15775/? A/DEBUG:     #01 pc 00000000  <unknown>

I think system call 142 is sys_newselect, which makes sense -- that's how runtime.usleep() is implemented. But I don't understand why select(2) would be denied by the seccomp policy on Android O. Has anyone else noticed this, any ideas? Thanks!

The text was updated successfully, but these errors were encountered:

cjb · 2017-05-18T18:23:48Z

Ah, I have a theory on what's happening. My theory is:

the new seccomp filter in Android O limits apps to using system calls that are exposed by Android's bionic libc: https://developer.android.com/preview/behavior-changes.html
bionic does not use select(2): https://android.googlesource.com/platform/bionic.git/+/master/libc/SYSCALLS.TXT
It wraps select(2) with pselect6(2) instead: https://android.googlesource.com/platform/bionic.git/+/master/libc/bionic/poll.cpp#78
because select(2) is not exposed by bionic, it is blocked by seccomp.
golang uses select(2) to implement runtime.usleep(), which results in the app being killed

So it seems like the potential fixes are:

Android adds sys_newselect to the syscall whitelist, even though it is not exposed by bionic.
Golang switches runtime.usleep to use pselect6(2) instead of select(2), perhaps only on Android.

(1) seems preferable to me.

bradfitz · 2017-05-18T18:28:46Z

The Go project can much more easily do (2) than (1).

cjb · 2017-05-18T18:34:38Z

Yeah, certainly true. (2) is quite a large change -- there's an argument change (struct timespec vs. struct timeval) as well as the syscall number, across every runtime/sys_linux_*.s.

Well, maybe we could limit the change to runtime/sys_linux_{amd64,arm,arm64}.s. I think those are the only platforms that can run Android?

What do you think? Thanks.

bradfitz · 2017-05-18T18:42:06Z

pselect was added to Linux in kernel 2.6.16 and Go requires 2.6.23 or later, so that seems fine to me at least.

@aclements, @ianlancetaylor?

aclements · 2017-05-18T20:30:06Z

It makes me sad, but, yes, we could pretty easily switch to pselect. In fact, linux/arm64 already uses pselect. Of course, Go binaries that haven't been recompiled won't work with Android O.

gopherbot · 2017-05-18T21:02:00Z

CL https://golang.org/cl/43641 mentions this issue.

eliasnaur · 2017-05-19T09:14:40Z

Could this be included in Go 1.9? Android O will probably be out (much) sooner than Go 1.10.

aclements · 2017-05-19T16:06:48Z

It will be included in Go 1.9.

A more interesting question is whether we should include this in Go 1.8.3. I'll reopen this on Go 1.8.3 for consideration.

cjb · 2017-05-22T19:44:16Z

@aclements Thanks for the quick fix! Verified that it works on device, but the simulator's still crashing -- even though I'm on an amd64 machine, gomobile compiles for 386 and that's what the Android simulator's using. So we'll need the same select()->pselect6() fix for sys_linux_386.s too.

bradfitz · 2017-05-23T21:24:18Z

Punting to maybe Go 1.8.4 since this reportedly doesn't work yet anyway and we're doing Go 1.8.3 today.

gopherbot · 2017-05-23T21:56:05Z

CL https://golang.org/cl/44011 mentions this issue.

cjb · 2017-05-23T22:08:59Z

Thanks very much! Tested CL 44011 working in the simulator.

bradfitz · 2017-05-23T22:20:59Z

@ianlancetaylor, is this something you're also comfortable backporting to the Go 1.8 branch?

ianlancetaylor · 2017-05-23T22:33:41Z

This is fine for 1.8 as far as I'm concerned.

aclements · 2017-05-23T22:49:37Z

Re-re-opened for cherry-pick.

gopherbot · 2017-05-23T22:50:42Z

CL https://golang.org/cl/44002 mentions this issue.

gopherbot · 2017-05-23T22:50:43Z

CL https://golang.org/cl/44001 mentions this issue.

…4 and linux/arm Android O black-lists the select system call because its libc, Bionic, does not use this system call. Replace our use of select with pselect6 (which is allowed) on the platforms that support targeting Android. linux/arm64 already uses pselect6 because there is no select on arm64, so only linux/amd64 and linux/arm need changing. pselect6 has been available since Linux 2.6.16, which is before Go's minimum requirement. Fixes #20409. Change-Id: Ic526b5b259a9e01d2f145a1f4d2e76e8c49ce809 Reviewed-on: https://go-review.googlesource.com/43641 Run-TryBot: Austin Clements <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Brad Fitzpatrick <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> (cherry picked from commit 4dcba02) Reviewed-on: https://go-review.googlesource.com/44001 Run-TryBot: Brad Fitzpatrick <[email protected]> Reviewed-by: Chris Broadfoot <[email protected]>

Commit 4dcba02 replaced select with pselect6 on linux/amd64 and linux/arm, but it turns out the Android emulator uses linux/386. This makes the equivalent change there, too. Fixes #20409 more. Change-Id: If542d6ade06309aab8758d5f5f6edec201ca7670 Reviewed-on: https://go-review.googlesource.com/44011 Run-TryBot: Austin Clements <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Brad Fitzpatrick <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> (cherry picked from commit ecad34a40ea390ddf5ba2da8f3c3f2c5f15297c8) Reviewed-on: https://go-review.googlesource.com/44002 Run-TryBot: Brad Fitzpatrick <[email protected]> Reviewed-by: Chris Broadfoot <[email protected]>

gopherbot added this to the Unreleased milestone May 18, 2017

bradfitz modified the milestones: Go1.10, Unreleased May 18, 2017

gopherbot closed this as completed in 4dcba02 May 19, 2017

aclements reopened this May 19, 2017

aclements modified the milestones: Go1.8.3, Go1.10 May 19, 2017

cjb mentioned this issue May 20, 2017

Crashes on open with Android O keybase/client#7072

Open

bradfitz modified the milestones: Go1.8.4, Go1.8.3 May 23, 2017

gopherbot closed this as completed in e26b51b May 23, 2017

bradfitz modified the milestones: Go1.8.3, Go1.8.4 May 23, 2017

aclements reopened this May 23, 2017

broady closed this as completed May 24, 2017

dawndiy mentioned this issue Feb 4, 2018

x/mobile: gomobile Apps crash on Android 8 at "runtime/internal/atomic.Cas" #23692

Open

eliasnaur mentioned this issue Mar 15, 2018

x/mobile: seccomp filters os.Stat and print/println/panic on amd64 Android O #24403

Closed

golang locked and limited conversation to collaborators May 24, 2018

gopherbot added the FrozenDueToAge label May 24, 2018

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x/mobile: gomobile apps crash inside runtime.usleep() on Android O beta #20409

x/mobile: gomobile apps crash inside runtime.usleep() on Android O beta #20409

cjb commented May 18, 2017

cjb commented May 18, 2017 •

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aclements commented May 19, 2017

cjb commented May 22, 2017

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cjb commented May 23, 2017

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ianlancetaylor commented May 23, 2017

aclements commented May 23, 2017

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gopherbot commented May 23, 2017

x/mobile: gomobile apps crash inside runtime.usleep() on Android O beta #20409

x/mobile: gomobile apps crash inside runtime.usleep() on Android O beta #20409

Comments

cjb commented May 18, 2017

What version of Go are you using (go version)?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

cjb commented May 18, 2017 • edited Loading

bradfitz commented May 18, 2017

cjb commented May 18, 2017 • edited Loading

bradfitz commented May 18, 2017

aclements commented May 18, 2017

gopherbot commented May 18, 2017

eliasnaur commented May 19, 2017

aclements commented May 19, 2017

cjb commented May 22, 2017

bradfitz commented May 23, 2017

gopherbot commented May 23, 2017

cjb commented May 23, 2017

bradfitz commented May 23, 2017

ianlancetaylor commented May 23, 2017

aclements commented May 23, 2017

gopherbot commented May 23, 2017

gopherbot commented May 23, 2017

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?

cjb commented May 18, 2017 •

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cjb commented May 18, 2017 •

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