On Tue, Jul 07, 2009 at 09:18:36PM +0300, Avi Kivity wrote: > On 07/07/2009 09:15 PM, Peter Zijlstra wrote: >> On Tue, 2009-07-07 at 15:06 -0300, Marcelo Tosatti wrote: >> >>> KVM guests with CONFIG_LOCKDEP=y trigger the following warning: >>> >>> BUG: MAX_LOCK_DEPTH too low! >>> turning off the locking correctness validator. >>> Pid: 4624, comm: qemu-system-x86 Not tainted 2.6.31-rc2-03981-g3abaf21 >>> #32 >>> Call Trace: >>> [<ffffffff81068bab>] __lock_acquire+0x1559/0x15fc >>> [<ffffffff810be4d9>] ? mm_take_all_locks+0x99/0x109 >>> [<ffffffff810be4d9>] ? mm_take_all_locks+0x99/0x109 >>> [<ffffffff81068d3c>] lock_acquire+0xee/0x112 >>> [<ffffffff810be516>] ? mm_take_all_locks+0xd6/0x109 >>> [<ffffffff81402596>] ? _spin_lock_nest_lock+0x20/0x50 >>> [<ffffffff814025b7>] _spin_lock_nest_lock+0x41/0x50 >>> [<ffffffff810be516>] ? mm_take_all_locks+0xd6/0x109 >>> [<ffffffff810be516>] mm_take_all_locks+0xd6/0x109 >>> [<ffffffff810d0f76>] do_mmu_notifier_register+0xd4/0x199 >>> [<ffffffff810d1060>] mmu_notifier_register+0x13/0x15 >>> [<ffffffffa0107f16>] kvm_dev_ioctl+0x13f/0x30e [kvm] >>> [<ffffffff810e6a3a>] vfs_ioctl+0x2f/0x7d >>> [<ffffffff810e6fb7>] do_vfs_ioctl+0x4af/0x4ec >>> [<ffffffff814030b4>] ? error_exit+0x94/0xb0 >>> [<ffffffff81401f92>] ? trace_hardirqs_off_thunk+0x3a/0x3c >>> [<ffffffff8100bc2d>] ? retint_swapgs+0xe/0x13 >>> [<ffffffff810e703b>] sys_ioctl+0x47/0x6a >>> [<ffffffff811d849c>] ? __up_read+0x1a/0x85 >>> [<ffffffff8100b1db>] system_call_fastpath+0x16/0x1b >>> >>> Since mm_take_all_locks takes a gazillion locks. >>> >>> Is there any way around this other than completly shutting down lockdep? >>> >> >> When we created this the promise was that kvm would only do this on a >> fresh mm with only a few vmas, has that changed > > The number of vmas did increase, but not materially. We do link with > more shared libraries though. Yeah, see attached /proc/pid/maps just before the ioctl thats ends up in mmu_notifier_register. mm_take_all_locks: file_vma=79 anon_vma=40
00400000-005f7000 r-xp 00000000 fe:00 35325942 /home/marcelo/git/kvm-userspace/qemu/x86_64-softmmu/qemu-system-x86_64 007f7000-007fd000 rw-p 001f7000 fe:00 35325942 /home/marcelo/git/kvm-userspace/qemu/x86_64-softmmu/qemu-system-x86_64 007fd000-00c2b000 rw-p 00000000 00:00 0 [heap] 3694c00000-3694c1d000 r-xp 00000000 fe:00 55902220 /lib64/ld-2.8.so 3694e1c000-3694e1d000 r--p 0001c000 fe:00 55902220 /lib64/ld-2.8.so 3694e1d000-3694e1e000 rw-p 0001d000 fe:00 55902220 /lib64/ld-2.8.so 3695800000-369586b000 r-xp 00000000 fe:00 37007715 /usr/lib64/libSDL-1.2.so.0.11.2 369586b000-3695a6a000 ---p 0006b000 fe:00 37007715 /usr/lib64/libSDL-1.2.so.0.11.2 3695a6a000-3695a6d000 rw-p 0006a000 fe:00 37007715 /usr/lib64/libSDL-1.2.so.0.11.2 3695a6d000-3695a9d000 rw-p 00000000 00:00 0 3695e00000-3695f62000 r-xp 00000000 fe:00 55902230 /lib64/libc-2.8.so 3695f62000-3696162000 ---p 00162000 fe:00 55902230 /lib64/libc-2.8.so 3696162000-3696166000 r--p 00162000 fe:00 55902230 /lib64/libc-2.8.so 3696166000-3696167000 rw-p 00166000 fe:00 55902230 /lib64/libc-2.8.so 3696167000-369616c000 rw-p 00000000 00:00 0 3696200000-3696284000 r-xp 00000000 fe:00 55902232 /lib64/libm-2.8.so 3696284000-3696483000 ---p 00084000 fe:00 55902232 /lib64/libm-2.8.so 3696483000-3696484000 r--p 00083000 fe:00 55902232 /lib64/libm-2.8.so 3696484000-3696485000 rw-p 00084000 fe:00 55902232 /lib64/libm-2.8.so 3696600000-3696602000 r-xp 00000000 fe:00 55902236 /lib64/libdl-2.8.so 3696602000-3696802000 ---p 00002000 fe:00 55902236 /lib64/libdl-2.8.so 3696802000-3696803000 r--p 00002000 fe:00 55902236 /lib64/libdl-2.8.so 3696803000-3696804000 rw-p 00003000 fe:00 55902236 /lib64/libdl-2.8.so 3696a00000-3696a16000 r-xp 00000000 fe:00 55902321 /lib64/libpthread-2.8.so 3696a16000-3696c15000 ---p 00016000 fe:00 55902321 /lib64/libpthread-2.8.so 3696c15000-3696c16000 r--p 00015000 fe:00 55902321 /lib64/libpthread-2.8.so 3696c16000-3696c17000 rw-p 00016000 fe:00 55902321 /lib64/libpthread-2.8.so 3696c17000-3696c1b000 rw-p 00000000 00:00 0 3697200000-3697215000 r-xp 00000000 fe:00 55902316 /lib64/libz.so.1.2.3 3697215000-3697414000 ---p 00015000 fe:00 55902316 /lib64/libz.so.1.2.3 3697414000-3697415000 rw-p 00014000 fe:00 55902316 /lib64/libz.so.1.2.3 3697e00000-3697e05000 r-xp 00000000 fe:00 37003255 /usr/lib64/libXdmcp.so.6.0.0 3697e05000-3698004000 ---p 00005000 fe:00 37003255 /usr/lib64/libXdmcp.so.6.0.0 3698004000-3698005000 rw-p 00004000 fe:00 37003255 /usr/lib64/libXdmcp.so.6.0.0 3698200000-369821a000 r-xp 00000000 fe:00 37003257 /usr/lib64/libxcb.so.1.0.0 369821a000-369841a000 ---p 0001a000 fe:00 37003257 /usr/lib64/libxcb.so.1.0.0 369841a000-369841b000 rw-p 0001a000 fe:00 37003257 /usr/lib64/libxcb.so.1.0.0 3698600000-3698602000 r-xp 00000000 fe:00 37003253 /usr/lib64/libXau.so.6.0.0 3698602000-3698801000 ---p 00002000 fe:00 37003253 /usr/lib64/libXau.so.6.0.0 3698801000-3698802000 rw-p 00001000 fe:00 37003253 /usr/lib64/libXau.so.6.0.0 3698a00000-3698b06000 r-xp 00000000 fe:00 37003260 /usr/lib64/libX11.so.6.2.0 3698b06000-3698d05000 ---p 00106000 fe:00 37003260 /usr/lib64/libX11.so.6.2.0 3698d05000-3698d0b000 rw-p 00105000 fe:00 37003260 /usr/lib64/libX11.so.6.2.0 3698e00000-3698e01000 r-xp 00000000 fe:00 37003259 /usr/lib64/libxcb-xlib.so.0.0.0 3698e01000-3699000000 ---p 00001000 fe:00 37003259 /usr/lib64/libxcb-xlib.so.0.0.0 3699000000-3699001000 rw-p 00000000 fe:00 37003259 /usr/lib64/libxcb-xlib.so.0.0.0 369f600000-369f611000 r-xp 00000000 fe:00 55902471 /lib64/libresolv-2.8.so 369f611000-369f811000 ---p 00011000 fe:00 55902471 /lib64/libresolv-2.8.so 369f811000-369f812000 r--p 00011000 fe:00 55902471 /lib64/libresolv-2.8.so 369f812000-369f813000 rw-p 00012000 fe:00 55902471 /lib64/libresolv-2.8.so 369f813000-369f815000 rw-p 00000000 00:00 0 36a2600000-36a2602000 r-xp 00000000 fe:00 55902548 /lib64/libutil-2.8.so 36a2602000-36a2801000 ---p 00002000 fe:00 55902548 /lib64/libutil-2.8.so 36a2801000-36a2802000 r--p 00001000 fe:00 55902548 /lib64/libutil-2.8.so 36a2802000-36a2803000 rw-p 00002000 fe:00 55902548 /lib64/libutil-2.8.so 36a4a00000-36a4a09000 r-xp 00000000 fe:00 55902514 /lib64/libcrypt-2.8.so 36a4a09000-36a4c08000 ---p 00009000 fe:00 55902514 /lib64/libcrypt-2.8.so 36a4c08000-36a4c09000 r--p 00008000 fe:00 55902514 /lib64/libcrypt-2.8.so 36a4c09000-36a4c0a000 rw-p 00009000 fe:00 55902514 /lib64/libcrypt-2.8.so 36a4c0a000-36a4c38000 rw-p 00000000 00:00 0 36a6200000-36a6221000 r-xp 00000000 fe:00 55902277 /lib64/libncurses.so.5.6 36a6221000-36a6421000 ---p 00021000 fe:00 55902277 /lib64/libncurses.so.5.6 36a6421000-36a6422000 rw-p 00021000 fe:00 55902277 /lib64/libncurses.so.5.6 36aae00000-36aae64000 r-xp 00000000 fe:00 55903029 /lib64/libgcrypt.so.11.4.3 36aae64000-36ab063000 ---p 00064000 fe:00 55903029 /lib64/libgcrypt.so.11.4.3 36ab063000-36ab066000 rw-p 00063000 fe:00 55903029 /lib64/libgcrypt.so.11.4.3 36aba00000-36aba1c000 r-xp 00000000 fe:00 55902546 /lib64/libtinfo.so.5.6 36aba1c000-36abc1c000 ---p 0001c000 fe:00 55902546 /lib64/libtinfo.so.5.6 36abc1c000-36abc20000 rw-p 0001c000 fe:00 55902546 /lib64/libtinfo.so.5.6 36aca00000-36aca19000 r-xp 00000000 fe:00 37003770 /usr/lib64/libsasl2.so.2.0.22 36aca19000-36acc19000 ---p 00019000 fe:00 37003770 /usr/lib64/libsasl2.so.2.0.22 36acc19000-36acc1a000 rw-p 00019000 fe:00 37003770 /usr/lib64/libsasl2.so.2.0.22 3794800000-379487b000 r-xp 00000000 fe:00 3342887 /usr/lib64/libgnutls.so.13.9.1 379487b000-3794a7a000 ---p 0007b000 fe:00 3342887 /usr/lib64/libgnutls.so.13.9.1 3794a7a000-3794a85000 rw-p 0007a000 fe:00 3342887 /usr/lib64/libgnutls.so.13.9.1 3797a00000-3797a07000 r-xp 00000000 fe:00 47317353 /lib64/librt-2.8.so 3797a07000-3797c07000 ---p 00007000 fe:00 47317353 /lib64/librt-2.8.so 3797c07000-3797c08000 r--p 00007000 fe:00 47317353 /lib64/librt-2.8.so 3797c08000-3797c09000 rw-p 00008000 fe:00 47317353 /lib64/librt-2.8.so 3798200000-3798210000 r-xp 00000000 fe:00 3342886 /usr/lib64/libtasn1.so.3.0.14 3798210000-379840f000 ---p 00010000 fe:00 3342886 /usr/lib64/libtasn1.so.3.0.14 379840f000-3798410000 rw-p 0000f000 fe:00 3342886 /usr/lib64/libtasn1.so.3.0.14 7f7b2d7d5000-7f7b2d7da000 rw-p 00000000 00:00 0 7f7b2d7da000-7f7b2d7dd000 r-xp 00000000 fe:00 55902991 /lib64/libgpg-error.so.0.4.0 7f7b2d7dd000-7f7b2d9dc000 ---p 00003000 fe:00 55902991 /lib64/libgpg-error.so.0.4.0 7f7b2d9dc000-7f7b2d9dd000 rw-p 00002000 fe:00 55902991 /lib64/libgpg-error.so.0.4.0 7f7b2d9dd000-7f7b2d9e2000 rw-p 00000000 00:00 0 7f7b2da06000-7f7b2da08000 rw-p 00000000 00:00 0 7fffe0cdb000-7fffe0cf0000 rw-p 00000000 00:00 0 [stack] 7fffe0d93000-7fffe0d94000 r-xp 00000000 00:00 0 [vdso] ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
