5.8 kernel running on a QEMU KVM Virtual Machine, arm64, gcov enabled: CONFIG_GCOV_KERNEL=y CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y CONFIG_GCOV_PROFILE_ALL=y running: sudo lcov --zerocounters ..causes the following splat: [ 78.634926] Unable to handle kernel write to read-only memory at virtual address ffffd764f255bb10 [ 78.639076] Mem abort info: [ 78.640313] ESR = 0x9600004e [ 78.641656] EC = 0x25: DABT (current EL), IL = 32 bits [ 78.644351] SET = 0, FnV = 0 [ 78.645766] EA = 0, S1PTW = 0 [ 78.649526] Data abort info: [ 78.654341] ISV = 0, ISS = 0x0000004e [ 78.656851] CM = 0, WnR = 1 [ 78.659043] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000b775f000 [ 78.665822] [ffffd764f255bb10] pgd=00000001b6fff003, p4d=00000001b6fff003, pud=00000001b6ffe003, pmd=00400000b5000f91 [ 78.677367] Internal error: Oops: 9600004e [#1] SMP [ 78.681204] Modules linked in: nls_iso8859_1 dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua efi_pstore qemu_fw_cfg sch_fq_codel drm virtio_rng ip_t ables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor xor_neon raid6_pq libcrc32c rai d1 raid0 multipath linear crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce virtio_net xhci_pci net_failover virtio_blk virtio_scsi failover xhci_pci_ren esas aes_neon_bs aes_neon_blk aes_ce_blk crypto_simd cryptd aes_ce_cipher [ 78.722642] CPU: 14 PID: 1175 Comm: lcov Tainted: G W 5.8.0-8-generic #9 [ 78.729364] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 78.733467] pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--) [ 78.736219] pc : __memset+0x148/0x188 [ 78.737993] lr : gcov_info_reset+0xa0/0x110 [ 78.740037] sp : ffff800010e53bf0 [ 78.741624] x29: ffff800010e53bf0 x28: ffff00015a648000 [ 78.744181] x27: 0000000000000000 x26: ffffd764e3df4060 [ 78.746776] x25: 0000000000000001 x24: ffffd764e3df4040 [ 78.749310] x23: 0000000000000000 x22: ffffd764e3df40a8 [ 78.751976] x21: ffffd764f6295db8 x20: ffffd764e3df4068 [ 78.754642] x19: ffffd764e3df4068 x18: 0000000000000000 [ 78.757265] x17: 0000000000000000 x16: 0000000000000000 [ 78.759922] x15: 0000000000000000 x14: 0000000000000000 [ 78.762585] x13: 0000000000000000 x12: 0000000000000000 [ 78.765209] x11: 0000000000000000 x10: 0000000000000000 [ 78.767861] x9 : 0000000000000000 x8 : ffffd764f255bb10 [ 78.770518] x7 : 0000000000000000 x6 : 000000000000003f [ 78.773135] x5 : 0000000000000040 x4 : 0000000000000030 [ 78.775793] x3 : 000000071ef97fd0 x2 : 000000071ef97fd0 [ 78.778449] x1 : 0000000000000000 x0 : ffffd764f255bb10 [ 78.781075] Call trace: [ 78.782329] __memset+0x148/0x188 [ 78.783980] reset_node+0x70/0xc0 [ 78.785628] reset_write+0xc0/0x130 [ 78.787397] full_proxy_write+0x98/0x110 [ 78.789354] vfs_write+0x18c/0x3e0 [ 78.791086] ksys_write+0xc4/0x1f0 [ 78.792778] __arm64_sys_write+0x44/0x60 [ 78.794771] invoke_syscall+0x74/0x150 [ 78.796639] el0_svc_common.constprop.0+0x94/0x264 [ 78.799049] do_el0_svc+0x5c/0x7c [ 78.800702] el0_svc+0x70/0x114 [ 78.802311] el0_sync_handler+0x140/0x39c [ 78.804304] el0_sync+0x17c/0x180 [ 78.805967] Code: f101007f fa45a068 54fffc0b aa0303e2 (a9001d07) [ 78.809019] ---[ end trace b9a826b707c133e4 ]---
Just spotted that earlier in the boot we get: [ 8.808508] virtio_blk virtio3: [vda] 209715200 512-byte logical blocks (107 GB/100 GiB) [ 8.808649] ------------[ cut here ]------------ [ 8.815777] vda: detected capacity change from 0 to 107374182400 [ 8.816623] WARNING: CPU: 3 PID: 212 at mm/page_alloc.c:4813 __alloc_pages_nodemask+0x540/0x694 [ 8.816630] Modules linked in: net_failover virtio_blk(+) xhci_pci_renesas virtio_scsi(+) failover fjes(-) aes_neon_bs aes_neon_blk aes_ce_blk crypto_s imd cryptd aes_ce_cipher [ 8.837701] CPU: 3 PID: 212 Comm: systemd-udevd Not tainted 5.8.0-8-generic #9 [ 8.842236] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 8.846585] pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--) [ 8.850112] pc : __alloc_pages_nodemask+0x540/0x694 [ 8.853106] lr : alloc_pages_current+0xe0/0x17c [ 8.856024] sp : ffff8000106138c0 [ 8.858175] x29: ffff8000106138c0 x28: ffff000170252dc0 [ 8.861565] x27: 0000000000000000 x26: 0000000000000015 [ 8.865006] x25: 00000001abcfef80 x24: 0000000000000015 [ 8.868466] x23: ffff000170252dc0 x22: 0000000000000000 [ 8.871794] x21: ffffdb2796703050 x20: 0000000000040dc0 [ 8.875143] x19: ffffdb2796703250 x18: 0000000000000000 [ 8.878529] x17: 0000000000000000 x16: 0000000000000000 [ 8.881917] x15: 0000000000000000 x14: 73656a662f74656e [ 8.885218] x13: 2f73726576697264 x12: 2f636972656e6567 [ 8.888554] x11: 2d646c6975622f64 x10: 6c6975622f6e6169 [ 8.892032] x9 : ffffdb2792b6dfa4 x8 : 63672e7366677562 [ 8.895415] x7 : 65645f73656a662f x6 : ffff0001558ef353 [ 8.898814] x5 : 0000000000000018 x4 : 0000000000000dd5 [ 8.902124] x3 : ffffdb27966ea138 x2 : 0000000000000001 [ 8.905418] x1 : ffffdb27966ea030 x0 : 0000000000000001 [ 8.908698] Call trace: [ 8.910278] __alloc_pages_nodemask+0x540/0x694 [ 8.913278] alloc_pages_current+0xe0/0x17c [ 8.915967] kmalloc_order+0x48/0xec [ 8.918325] kmalloc_order_trace+0x54/0x21c [ 8.921165] __kmalloc+0x454/0x5c0 [ 8.923368] kmalloc_array.constprop.0+0x30/0x50 [ 8.926301] gcov_info_dup+0x98/0x2c0 [ 8.928557] remove_info+0x1e0/0x244 [ 8.930876] gcov_event+0xfc/0x170 [ 8.933097] gcov_module_notifier+0x164/0x174 [ 8.935848] notifier_call_chain+0xa0/0x110 [ 8.938435] blocking_notifier_call_chain+0x80/0xe0 [ 8.941579] do_init_module+0x360/0x43c [ 8.944198] load_module+0x8fc/0xa50 [ 8.946591] __do_sys_finit_module+0x190/0x1c0 [ 8.949485] __arm64_sys_finit_module+0x48/0x64 [ 8.952376] invoke_syscall+0x74/0x150 [ 8.954901] el0_svc_common.constprop.0+0x94/0x264 [ 8.956405] sr 0:0:0:0: Power-on or device reset occurred [ 8.957610] do_el0_svc+0x5c/0x7c [ 8.960983] sr 0:0:0:0: [sr0] scsi3-mmc drive: 16x/50x cd/rw xa/form2 cdda tray [ 8.962169] el0_svc+0x70/0x114 [ 8.965694] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 8.967253] el0_sync_handler+0x140/0x39c [ 8.971738] el0_sync+0x17c/0x180 [ 8.973450] ---[ end trace 267579295e47a82a ]--- [ 8.976042] gcov: could not save data for '/home/cking/unstable/debian/build/build-generic/drivers/net/fjes/fjes_debugfs.gcda' (out of memory) [ 8.986263] gcov: could not save data for '/home/cking/unstable/debian/build/build-generic/drivers/net/fjes/fjes_trace.gcda' (out of memory) [ 8.996162] gcov: could not save data for '/home/cking/unstable/debian/build/build-generic/drivers/net/fjes/fjes_ethtool.gcda' (out of memory) [ 9.006231] gcov: could not save data for '/home/cking/unstable/debian/build/build-generic/drivers/net/fjes/fjes_hw.gcda' (out of memory) [ 9.010491] sr 0:0:0:0: Attached scsi CD-ROM sr0 [ 9.013246] sr 0:0:0:0: Attached scsi generic sg0 type 5 [ 9.014959] gcov: could not save data for '/home/cking/unstable/debian/build/build-generic/drivers/net/fjes/fjes_main.gcda' (out of memory)
I upped the VM memory to 16GB and reduced the CPU count to 1 CPU and still hit the out of memory condition with gcov.