ci starts bisection 2023-12-12 15:45:00.270125436 +0000 UTC m=+11863.880521997 bisecting cause commit starting from abb240f7a2bd14567ab53e602db562bb683391e6 building syzkaller on 28b24332d95f2f7df44ec7e7a5e0025bcadc6277 ensuring issue is reproducible on original commit abb240f7a2bd14567ab53e602db562bb683391e6 testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: d5d3e54c1d16073f930eaaa908630bef4e499311bfb723273891b1414d803565 all runs: crashed: general protection fault in bio_first_folio representative crash: general protection fault in bio_first_folio, types: [UNKNOWN] check whether we can drop unnecessary instrumentation disabling configs for [KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 6ac7a406ed2b7cbdbc5de6f2c077b4c32ff6af4c39000a6329a6269fc794679f all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the bug reproduces without the instrumentation disabling configs for [LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP HANG], they are not needed kconfig minimization: base=3923 full=7678 leaves diff=2007 split chunks (needed=false): <2007> split chunk #0 of len 2007 into 5 parts testing without sub-chunk 1/5 disabling configs for [HANG LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: ba3cbb18923d7864e20f035dda3d88018b2c6c060f911bef9f4f240cd8be0d25 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [BUG KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 98a8f6c52a1081d3a8f8870bbf6266df1f0fe59734292bb2d3c867878ef40112 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 3/5 disabling configs for [BUG KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 5262431abbff5ebb7afdf216131fc6fe02b99a69540ea268dc307fc9336649d7 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 4/5 disabling configs for [ATOMIC_SLEEP HANG LEAK UBSAN BUG KASAN LOCKDEP], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 0306a635b7e300e814f6d20a9ba24987ea6a92e2f4355b42a4b4143c8d9c5fbb all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [HANG LEAK UBSAN BUG KASAN LOCKDEP ATOMIC_SLEEP], they are not needed testing commit abb240f7a2bd14567ab53e602db562bb683391e6 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 1711791ffff14f2f781df5a5d120e0af4b0db4141ec3d4119003aa95c605aec2 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] the chunk can be dropped disabling configs for [KASAN LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG], they are not needed picked [v6.6 v6.5 v6.4 v6.2 v6.0 v5.18 v5.16 v5.14 v5.11 v5.8 v5.5 v5.2 v4.20 v4.19] out of 29 release tags testing release v6.6 testing commit ffc253263a1375a65fa6c9f62a893e9767fbebfa gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 4830bbe5c04e0f352e3c1e309e5c735bf5080438c9b74a767733a4192139dc54 all runs: OK false negative chance: 0.000 # git bisect start abb240f7a2bd14567ab53e602db562bb683391e6 ffc253263a1375a65fa6c9f62a893e9767fbebfa Bisecting: 12206 revisions left to test after this (roughly 14 steps) [ecae0bd5173b1014f95a14a8dfbe40ec10367dcf] Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm testing commit ecae0bd5173b1014f95a14a8dfbe40ec10367dcf gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: a440e95b28b3d2feedb92a246b10be6176322854146e228e86071a97223aacbf all runs: OK false negative chance: 0.000 # git bisect good ecae0bd5173b1014f95a14a8dfbe40ec10367dcf Bisecting: 6093 revisions left to test after this (roughly 13 steps) [802bb7d941d3a01c68a9e73a109419b041835e04] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git testing commit 802bb7d941d3a01c68a9e73a109419b041835e04 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: e6f1e6926ddf18a7ab3debb35484d32d2e2f3c9a4b349e3ad96ef7781e4467f0 all runs: OK false negative chance: 0.000 # git bisect good 802bb7d941d3a01c68a9e73a109419b041835e04 Bisecting: 3155 revisions left to test after this (roughly 12 steps) [3acf9f5199550b3a7fdfc8dd0664aa2368faf210] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git testing commit 3acf9f5199550b3a7fdfc8dd0664aa2368faf210 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 985d1b911b1be5d884de3798385ff307d4990292bea6c408f797f90b8efd0751 all runs: OK false negative chance: 0.000 # git bisect good 3acf9f5199550b3a7fdfc8dd0664aa2368faf210 Bisecting: 1621 revisions left to test after this (roughly 11 steps) [dc13b941ffc243d310034a310eea05f98ddf9ded] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git testing commit dc13b941ffc243d310034a310eea05f98ddf9ded gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 48e1dd24ca5c9e6be4219a52d59f3dfcd2cc6cce95198f4624c3aaff6a4e102b all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] # git bisect bad dc13b941ffc243d310034a310eea05f98ddf9ded Bisecting: 774 revisions left to test after this (roughly 10 steps) [069b3a5eb434ddd5db5e4ec15419b0c0f1d7ed56] Merge branch 'for-linux-next' of git://anongit.freedesktop.org/drm/drm-misc testing commit 069b3a5eb434ddd5db5e4ec15419b0c0f1d7ed56 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: a7d398d35fd8321751ea07696b7a0c45543977c7de3265b76f9f068408736d1f all runs: OK false negative chance: 0.000 # git bisect good 069b3a5eb434ddd5db5e4ec15419b0c0f1d7ed56 Bisecting: 305 revisions left to test after this (roughly 9 steps) [a07580117f97a656e11b00044d83946fe4aba329] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git testing commit a07580117f97a656e11b00044d83946fe4aba329 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: b08604353e092f37e299bb2b6a919f146216d3c3c2682d3334e8bb06c14d2815 all runs: OK false negative chance: 0.000 # git bisect good a07580117f97a656e11b00044d83946fe4aba329 Bisecting: 150 revisions left to test after this (roughly 7 steps) [b1fd37b2e53d8d447d71b740000ca03cfb1f6e87] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git testing commit b1fd37b2e53d8d447d71b740000ca03cfb1f6e87 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 059d2375083a3fef480f85805ba0df32e49d9182b6d156c34358cf6c5b8e50fd all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] # git bisect bad b1fd37b2e53d8d447d71b740000ca03cfb1f6e87 Bisecting: 75 revisions left to test after this (roughly 6 steps) [6a66656f60c8d6175df4c6edf3a73b24dae8f97f] Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git testing commit 6a66656f60c8d6175df4c6edf3a73b24dae8f97f gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 89f0db4e329fc654f2b9c6b27c41d7ff69e7aaaa5eb90c30b56895a35aa33440 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] # git bisect bad 6a66656f60c8d6175df4c6edf3a73b24dae8f97f Bisecting: 30 revisions left to test after this (roughly 5 steps) [0535ce8cdb537a658dd5d9820df344209826e1e5] Merge branch 'for-6.8/io_uring' into for-next testing commit 0535ce8cdb537a658dd5d9820df344209826e1e5 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: c49a7f797f28eba56887835786a06a77729f92b22c48e85aa84a1fa0bbd65e8c all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] # git bisect bad 0535ce8cdb537a658dd5d9820df344209826e1e5 Bisecting: 22 revisions left to test after this (roughly 5 steps) [2048a6344223b6d923fd52e367dbbddb1de46c6f] Merge branch 'vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs into for-6.8/io_uring testing commit 2048a6344223b6d923fd52e367dbbddb1de46c6f gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: ed3fe5403d1fb786bfe123e50c45dd36d198647289535f4f28cf21281d3ba99d all runs: OK false negative chance: 0.000 # git bisect good 2048a6344223b6d923fd52e367dbbddb1de46c6f Bisecting: 11 revisions left to test after this (roughly 4 steps) [726a9b67e9fb9a8e5c955b3d7d591becb23c47ee] Merge branch 'md-next-rcu-cleanup' into md-next testing commit 726a9b67e9fb9a8e5c955b3d7d591becb23c47ee gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 6f1a11e6ff591819a01d1d4d38d5321f78c4e4738c609dd8b91037e905e3066d all runs: OK false negative chance: 0.000 # git bisect good 726a9b67e9fb9a8e5c955b3d7d591becb23c47ee Bisecting: 5 revisions left to test after this (roughly 3 steps) [1b151e2435fc3a9b10c8946c6aebe9f3e1938c55] block: Remove special-casing of compound pages testing commit 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: e6362ff068438cc299fe1ca95c9c65df3d83b903f95b961dee6311d9676154ff all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages representative crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages, types: [UNKNOWN] # git bisect bad 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 Bisecting: 2 revisions left to test after this (roughly 2 steps) [e5da71f1e373f36c7506ffa9a60ef7ec6e84674d] iouring: remove IORING_URING_CMD_POLLED testing commit e5da71f1e373f36c7506ffa9a60ef7ec6e84674d gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 19da185b1c9a80443dcbe94761ba460185bafaf4b306d9ae2e8a01a417415fb2 all runs: OK false negative chance: 0.000 # git bisect good e5da71f1e373f36c7506ffa9a60ef7ec6e84674d Bisecting: 0 revisions left to test after this (roughly 1 step) [847c5bcdfb41704e52930783b028302f415a3209] block: skip QUEUE_FLAG_STATS and rq-qos for passthrough io testing commit 847c5bcdfb41704e52930783b028302f415a3209 gcc compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 kernel signature: 478784ef5afd4ebbc6520af8fdf9fd2c7b52d47928e393dcf1665a7026e44848 all runs: OK false negative chance: 0.000 # git bisect good 847c5bcdfb41704e52930783b028302f415a3209 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 is the first bad commit commit 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 Author: Matthew Wilcox (Oracle) Date: Mon Aug 14 15:41:00 2023 +0100 block: Remove special-casing of compound pages The special casing was originally added in pre-git history; reproducing the commit log here: > commit a318a92567d77 > Author: Andrew Morton > Date: Sun Sep 21 01:42:22 2003 -0700 > > [PATCH] Speed up direct-io hugetlbpage handling > > This patch short-circuits all the direct-io page dirtying logic for > higher-order pages. Without this, we pointlessly bounce BIOs up to > keventd all the time. In the last twenty years, compound pages have become used for more than just hugetlb. Rewrite these functions to operate on folios instead of pages and remove the special case for hugetlbfs; I don't think it's needed any more (and if it is, we can put it back in as a call to folio_test_hugetlb()). This was found by inspection; as far as I can tell, this bug can lead to pages used as the destination of a direct I/O read not being marked as dirty. If those pages are then reclaimed by the MM without being dirtied for some other reason, they won't be written out. Then when they're faulted back in, they will not contain the data they should. It'll take a pretty unusual setup to produce this problem with several races all going the wrong way. This problem predates the folio work; it could for example have been triggered by mmaping a THP in tmpfs and using that as the target of an O_DIRECT read. Fixes: 800d8c63b2e98 ("shmem: add huge pages support") Cc: Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Jens Axboe block/bio.c | 46 ++++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 22 deletions(-) accumulated error probability: 0.00 culprit signature: e6362ff068438cc299fe1ca95c9c65df3d83b903f95b961dee6311d9676154ff parent signature: 478784ef5afd4ebbc6520af8fdf9fd2c7b52d47928e393dcf1665a7026e44848 revisions tested: 22, total time: 6h13m5.460009031s (build: 3h35m6.445790065s, test: 2h23m15.281201309s) first bad commit: 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 block: Remove special-casing of compound pages recipients (to): ["axboe@kernel.dk" "axboe@kernel.dk" "linux-block@vger.kernel.org" "willy@infradead.org"] recipients (cc): ["linux-kernel@vger.kernel.org"] crash: BUG: unable to handle kernel NULL pointer dereference in __bio_release_pages BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 103f6d067 P4D 103f6d067 PUD 103f6f067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 1861 Comm: syz-executor.0 Not tainted 6.7.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:_compound_head include/linux/page-flags.h:247 [inline] RIP: 0010:bio_first_folio include/linux/bio.h:289 [inline] RIP: 0010:__bio_release_pages+0x33/0x2c0 block/bio.c:1150 Code: 06 00 00 00 41 56 41 55 41 54 55 48 89 fd 53 48 83 ec 40 48 8d 54 24 10 40 88 74 24 0f 48 89 d7 48 8b 55 68 f3 48 ab 48 8b 02 <48> 8b 48 08 f6 c1 01 0f 85 14 01 00 00 0f 1f 44 00 00 48 89 04 24 RSP: 0018:ffffc900012279f8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8881096f3f00 RCX: 0000000000000000 RDX: ffff8881096f3f78 RSI: 0000000000000000 RDI: ffffc90001227a38 RBP: ffff8881096f3f00 R08: 0000000000000008 R09: 000000001fffefff R10: 0000000000007ffc R11: 0000000000000000 R12: fffffffffffffff2 R13: ffff8881042fe000 R14: ffff8881042fe000 R15: 0000000000000000 FS: 00007fb4230226c0(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000104337000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bio_release_pages include/linux/bio.h:508 [inline] bio_map_user_iov+0x339/0x3a0 block/blk-map.c:347 blk_rq_map_user_iov+0xd7/0x7b0 block/blk-map.c:663 blk_rq_map_user block/blk-map.c:690 [inline] blk_rq_map_user_io+0xf6/0x100 block/blk-map.c:723 sg_io+0x16b/0x320 drivers/scsi/scsi_ioctl.c:456 scsi_cdrom_send_packet+0x1bc/0x310 drivers/scsi/scsi_ioctl.c:820 scsi_ioctl+0x96/0x950 drivers/scsi/scsi_ioctl.c:903 sg_ioctl+0x2f4/0xaf0 drivers/scsi/sg.c:1163 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x8b/0xc0 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7fb42349fba9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb4230220c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb4235bef80 RCX: 00007fb42349fba9 RDX: 0000000020000000 RSI: 0000000000005393 RDI: 0000000000000004 RBP: 00007fb4234eb47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000006 R14: 00007fb4235bef80 R15: 00007ffe87d3fb88 Modules linked in: CR2: 0000000000000008 ---[ end trace 0000000000000000 ]--- RIP: 0010:_compound_head include/linux/page-flags.h:247 [inline] RIP: 0010:bio_first_folio include/linux/bio.h:289 [inline] RIP: 0010:__bio_release_pages+0x33/0x2c0 block/bio.c:1150 Code: 06 00 00 00 41 56 41 55 41 54 55 48 89 fd 53 48 83 ec 40 48 8d 54 24 10 40 88 74 24 0f 48 89 d7 48 8b 55 68 f3 48 ab 48 8b 02 <48> 8b 48 08 f6 c1 01 0f 85 14 01 00 00 0f 1f 44 00 00 48 89 04 24 RSP: 0018:ffffc900012279f8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8881096f3f00 RCX: 0000000000000000 RDX: ffff8881096f3f78 RSI: 0000000000000000 RDI: ffffc90001227a38 RBP: ffff8881096f3f00 R08: 0000000000000008 R09: 000000001fffefff R10: 0000000000007ffc R11: 0000000000000000 R12: fffffffffffffff2 R13: ffff8881042fe000 R14: ffff8881042fe000 R15: 0000000000000000 FS: 00007fb4230226c0(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000104337000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 00 00 add %al,(%rax) 2: 00 41 56 add %al,0x56(%rcx) 5: 41 55 push %r13 7: 41 54 push %r12 9: 55 push %rbp a: 48 89 fd mov %rdi,%rbp d: 53 push %rbx e: 48 83 ec 40 sub $0x40,%rsp 12: 48 8d 54 24 10 lea 0x10(%rsp),%rdx 17: 40 88 74 24 0f mov %sil,0xf(%rsp) 1c: 48 89 d7 mov %rdx,%rdi 1f: 48 8b 55 68 mov 0x68(%rbp),%rdx 23: f3 48 ab rep stos %rax,%es:(%rdi) 26: 48 8b 02 mov (%rdx),%rax * 29: 48 8b 48 08 mov 0x8(%rax),%rcx <-- trapping instruction 2d: f6 c1 01 test $0x1,%cl 30: 0f 85 14 01 00 00 jne 0x14a 36: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 3b: 48 89 04 24 mov %rax,(%rsp)