Hi John, On 10/07/2019 10:47, Vincenzo Frascino wrote: > Hi John, > > On 10/07/2019 05:02, John Stultz wrote: >> On Fri, Jun 21, 2019 at 3:18 AM Vincenzo Frascino >> <vincenzo.frascino@xxxxxxx> wrote: >>> >>> Provide the arm64 compat (AArch32) vDSO in kernel/vdso32 in a similar >>> way to what happens in kernel/vdso. >>> >>> The compat vDSO leverages on an adaptation of the arm architecture code >>> with few changes: >>> - Use of lib/vdso for gettimeofday >>> - Implementation of syscall based fallback >>> - Introduction of clock_getres for the compat library >>> - Implementation of trampolines >>> - Implementation of elf note >>> >>> To build the compat vDSO a 32 bit compiler is required and needs to be >>> specified via CONFIG_CROSS_COMPILE_COMPAT_VDSO. >>> >> >> Hey Vincenzo! >> Congrats on getting this work merged, I know its been a long effort >> over a number of years! >> >> Though unfortunately, it seems the arm64 vdso code that just landed is >> breaking AOSP for me. >> >> I see a lot of the following errors: >> 01-01 01:22:14.097 755 755 F libc : Fatal signal 11 (SIGSEGV), >> code 1 (SEGV_MAPERR), fault addr 0x3cf2c96c in tid 755 (cameraserver), >> pid 755 (cameraserver) >> 01-01 01:22:14.112 759 759 F libc : Fatal signal 11 (SIGSEGV), >> code 1 (SEGV_MAPERR), fault addr 0x3cf2c96c in tid 759 >> (android.hardwar), pid 759 (android.hardwar) >> 01-01 01:22:14.120 756 756 F libc : Fatal signal 11 (SIGSEGV), >> code 1 (SEGV_MAPERR), fault addr 0x3cf2c96c in tid 756 (drmserver), >> pid 756 (drmserver) >> >> Which go away if I revert the vdso merge that went in via tip/timers. >> >> I tried to bisect things down a bit, but as some later fixes are >> required (at one point, date was returning the start epoch and never >> increasing), this hasn't worked too well. But I'm guessing since I >> see: "CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will >> not be built", and the system is half working, I'm guessing this is an >> issue with just the 32bit code failing. While I can try to sort out >> the proper CROSS_COMPILE_COMPAT in my build environment, I assume >> userland shouldn't be crashing if that value isn't set. >> >> Any chance this issue has already been raised? >> > > I do not have Android (bionic/libc) as part of my testing environment hence I > never saw this issue. Thanks for reporting it. > > I am investigating the problem and will post a fix as soon as it is ready. > > As Will suggested, .config would help the debugging and I would like to ask to > you to test my fix once it is ready. Is that OK for you? > >> thanks >> -john >> > Seems that the problem you are experiencing is caused by an ABI regression for which I provided a fix in [1]. Could you please verify that works for you as well? [1] https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg2046889.html Please find below the tests that I conducted to verify that when CROSS_COMPILE_COMPAT is not defined or empty the compat vdso library is not exposed. # cat main-arm32.c #include <stdio.h> #include <sys/auxv.h> int main() { uintptr_t vdso = (uintptr_t) getauxval(AT_SYSINFO_EHDR); printf("AT_SYSINFO_EHDR: %p\n", vdso); [...] return 0; } # file main-arm32 main-arm32: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-, for GNU/Linux 3.2.0, with d When CROSS_COMPILE_COMPAT is _not_ defined: =========================================== # ./main-arm32 AT_SYSINFO_EHDR: (nil) Memory Map: ----------- 00008000-00010000 rw-p 00000000 00:00 0 00010000-00011000 r-xp 00000000 00:13 24905929 /home/vinfra01/bin/main-arm32 00011000-00020000 rw-p 00000000 00:00 0 00020000-00021000 r--p 00000000 00:13 24905929 /home/vinfra01/bin/main-arm32 00021000-00022000 rw-p 00001000 00:13 24905929 /home/vinfra01/bin/main-arm32 00022000-f773d000 rw-p 00000000 00:00 0 [heap] f773d000-f781f000 r-xp 00000000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f781f000-f782f000 ---p 000e2000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f782f000-f7831000 r--p 000e2000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7831000-f7832000 rw-p 000e4000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7832000-f7835000 rw-p 00000000 00:00 0 f7835000-f784b000 rw-p 00000000 00:00 0 f784b000-f7863000 r-xp 00000000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7863000-f7870000 rw-p 00000000 00:00 0 f7870000-f7872000 rw-p 00000000 00:00 0 f7872000-f7873000 r-xp 00000000 00:00 0 [sigpage] f7873000-f7874000 r--p 00018000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7874000-f7875000 rw-p 00019000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7875000-ff77a000 rw-p 00000000 00:00 0 ff87a000-ff89b000 rw-p 00000000 00:00 0 [stack] ff89b000-ffff0000 rw-p 00000000 00:00 0 ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] ffff1000-fffff000 rw-p 00000000 00:00 0 vdsotest for compat [2]: ------------------------ Note: vDSO version of clock_gettime not found clock-gettime-monotonic: syscall: 796 nsec/call clock-gettime-monotonic: libc: 816 nsec/call clock-gettime-monotonic: vdso: not tested Note: vDSO version of clock_gettime not found Note: vDSO version of clock_gettime not found Note: vDSO version of clock_getres not found clock-getres-monotonic: syscall: 567 nsec/call clock-getres-monotonic: libc: 581 nsec/call clock-getres-monotonic: vdso: not tested Note: vDSO version of clock_getres not found Note: vDSO version of clock_getres not found Note: vDSO version of clock_gettime not found clock-gettime-monotonic-coarse: syscall: 617 nsec/call clock-gettime-monotonic-coarse: libc: 656 nsec/call clock-gettime-monotonic-coarse: vdso: not tested Note: vDSO version of clock_gettime not found Note: vDSO version of clock_gettime not found Note: vDSO version of clock_getres not found clock-getres-monotonic-coarse: syscall: 591 nsec/call clock-getres-monotonic-coarse: libc: 614 nsec/call clock-getres-monotonic-coarse: vdso: not tested Note: vDSO version of clock_getres not found Note: vDSO version of clock_getres not found Note: vDSO version of clock_gettime not found clock-gettime-realtime: syscall: 819 nsec/call clock-gettime-realtime: libc: 858 nsec/call clock-gettime-realtime: vdso: not tested Note: vDSO version of clock_gettime not found Note: vDSO version of clock_gettime not found Note: vDSO version of clock_getres not found clock-getres-realtime: syscall: 567 nsec/call clock-getres-realtime: libc: 583 nsec/call clock-getres-realtime: vdso: not tested Note: vDSO version of clock_getres not found Note: vDSO version of clock_getres not found Note: vDSO version of clock_gettime not found clock-gettime-realtime-coarse: syscall: 599 nsec/call clock-gettime-realtime-coarse: libc: 638 nsec/call clock-gettime-realtime-coarse: vdso: not tested Note: vDSO version of clock_gettime not found Note: vDSO version of clock_gettime not found Note: vDSO version of clock_getres not found clock-getres-realtime-coarse: syscall: 591 nsec/call clock-getres-realtime-coarse: libc: 610 nsec/call clock-getres-realtime-coarse: vdso: not tested Note: vDSO version of clock_getres not found Note: vDSO version of clock_getres not found Note: vDSO version of getcpu not found getcpu: syscall: 431 nsec/call getcpu: libc: 451 nsec/call getcpu: vdso: not tested Note: vDSO version of getcpu not found Note: vDSO version of getcpu not found Note: vDSO version of gettimeofday not found gettimeofday: syscall: 765 nsec/call gettimeofday: libc: 808 nsec/call gettimeofday: vdso: not tested Note: vDSO version of gettimeofday not found Note: vDSO version of gettimeofday not found When CROSS_COMPILE_COMPAT is defined: ===================================== # ./main-arm32 AT_SYSINFO_EHDR: 0xf7a67000 Memory map: ----------- 00008000-00010000 rw-p 00000000 00:00 0 00010000-00011000 r-xp 00000000 00:13 24905929 /home/vinfra01/bin/main-arm32 00011000-00020000 rw-p 00000000 00:00 0 00020000-00021000 r--p 00000000 00:13 24905929 /home/vinfra01/bin/main-arm32 00021000-00022000 rw-p 00001000 00:13 24905929 /home/vinfra01/bin/main-arm32 00022000-f7932000 rw-p 00000000 00:00 0 [heap] f7932000-f7a14000 r-xp 00000000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7a14000-f7a24000 ---p 000e2000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7a24000-f7a26000 r--p 000e2000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7a26000-f7a27000 rw-p 000e4000 00:13 24906912 /lib/arm-linux-gnueabihf/libc-2.27.so f7a27000-f7a2a000 rw-p 00000000 00:00 0 f7a2a000-f7a40000 rw-p 00000000 00:00 0 f7a40000-f7a58000 r-xp 00000000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7a58000-f7a64000 rw-p 00000000 00:00 0 f7a64000-f7a66000 rw-p 00000000 00:00 0 f7a66000-f7a67000 r--p 00000000 00:00 0 [vvar] f7a67000-f7a68000 r-xp 00000000 00:00 0 [vdso] f7a68000-f7a69000 r--p 00018000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7a69000-f7a6a000 rw-p 00019000 00:13 24906908 /lib/arm-linux-gnueabihf/ld-2.27.so f7a6a000-ff6d8000 rw-p 00000000 00:00 0 ff7d8000-ff7f9000 rw-p 00000000 00:00 0 [stack] ff7f9000-ffff0000 rw-p 00000000 00:00 0 ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] ffff1000-fffff000 rw-p 00000000 00:00 0 vdsotest for compat [2]: ------------------------ clock-gettime-monotonic: syscall: 700 nsec/call clock-gettime-monotonic: libc: 226 nsec/call clock-gettime-monotonic: vdso: 189 nsec/call clock-getres-monotonic: syscall: 582 nsec/call clock-getres-monotonic: libc: 581 nsec/call clock-getres-monotonic: vdso: 40 nsec/call clock-gettime-monotonic-coarse: syscall: 618 nsec/call clock-gettime-monotonic-coarse: libc: 103 nsec/call clock-gettime-monotonic-coarse: vdso: 85 nsec/call clock-getres-monotonic-coarse: syscall: 602 nsec/call clock-getres-monotonic-coarse: libc: 610 nsec/call clock-getres-monotonic-coarse: vdso: 64 nsec/call clock-gettime-realtime: syscall: 741 nsec/call clock-gettime-realtime: libc: 209 nsec/call clock-gettime-realtime: vdso: 189 nsec/call clock-getres-realtime: syscall: 627 nsec/call clock-getres-realtime: libc: 604 nsec/call clock-getres-realtime: vdso: 41 nsec/call clock-gettime-realtime-coarse: syscall: 640 nsec/call clock-gettime-realtime-coarse: libc: 105 nsec/call clock-gettime-realtime-coarse: vdso: 84 nsec/call clock-getres-realtime-coarse: syscall: 597 nsec/call clock-getres-realtime-coarse: libc: 608 nsec/call clock-getres-realtime-coarse: vdso: 46 nsec/call Note: vDSO version of getcpu not found getcpu: syscall: 492 nsec/call getcpu: libc: 492 nsec/call getcpu: vdso: not tested Note: vDSO version of getcpu not found Note: vDSO version of getcpu not found gettimeofday: syscall: 664 nsec/call gettimeofday: libc: 224 nsec/call gettimeofday: vdso: 185 nsec/call [2] https://github.com/nathanlynch/vdsotest -- Regards, Vincenzo
