bisecting fixing commit since 92ed301919932f777713b9172e525674157e983d building syzkaller on cb93dc6ac64225e09f44bac6c6cce1dae1b248b0 testing commit 92ed301919932f777713b9172e525674157e983d with gcc (GCC) 8.1.0 kernel signature: 94f365880e98d97bfff8ef006e20997213be7a2708c1b5c65a52b181e05423ee run #0: crashed: INFO: rcu detected stall in ext4_file_write_iter run #1: crashed: INFO: rcu detected stall in ext4_file_write_iter run #2: crashed: INFO: rcu detected stall in ext4_file_write_iter run #3: crashed: INFO: rcu detected stall in ext4_file_write_iter run #4: crashed: INFO: rcu detected stall in ext4_file_write_iter run #5: crashed: INFO: rcu detected stall in ext4_file_write_iter run #6: crashed: INFO: rcu detected stall in ext4_file_write_iter run #7: crashed: INFO: rcu detected stall in ext4_file_write_iter run #8: crashed: INFO: rcu detected stall in ext4_file_write_iter run #9: boot failed: can't ssh into the instance testing current HEAD 581cb3a26baf846ee9636214afaa5333919875b1 testing commit 581cb3a26baf846ee9636214afaa5333919875b1 with gcc (GCC) 8.1.0 kernel signature: 9a96aa7f5a37fcb3e0a2bfe82d2340ea6a234b4a8dc286d636a9e1f8e27802d1 all runs: OK # git bisect start 581cb3a26baf846ee9636214afaa5333919875b1 92ed301919932f777713b9172e525674157e983d Bisecting: 6652 revisions left to test after this (roughly 13 steps) [47ec5303d73ea344e84f46660fff693c57641386] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next testing commit 47ec5303d73ea344e84f46660fff693c57641386 with gcc (GCC) 8.1.0 kernel signature: 7c43115c0980742da77797e0a6f606e9493b1b9267bbd7c1576249984df9eb0d all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 47ec5303d73ea344e84f46660fff693c57641386 Bisecting: 3320 revisions left to test after this (roughly 12 steps) [32663c78c10f80df90b832de0428a6cb98a64e9a] Merge tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace testing commit 32663c78c10f80df90b832de0428a6cb98a64e9a with gcc (GCC) 8.1.0 kernel signature: df2f9012b4970226847c18ba1529f56f1a53a22b1637c3c5f1555867ecdff4b6 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 32663c78c10f80df90b832de0428a6cb98a64e9a Bisecting: 1677 revisions left to test after this (roughly 11 steps) [e764a1e32337aaf325fc5b14a5bbd06eabba4699] Merge branch 'i2c/for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux testing commit e764a1e32337aaf325fc5b14a5bbd06eabba4699 with gcc (GCC) 8.1.0 kernel signature: 6f04ff920d848707ff69cbfe080de4d98cebaa202fdbf95b6ab5a4f2f9fcdade run #0: crashed: INFO: rcu detected stall in ext4_file_write_iter run #1: crashed: INFO: rcu detected stall in ext4_file_write_iter run #2: crashed: INFO: rcu detected stall in ext4_file_write_iter run #3: crashed: INFO: rcu detected stall in ext4_file_write_iter run #4: crashed: INFO: rcu detected stall in ext4_file_write_iter run #5: crashed: INFO: rcu detected stall in ext4_file_write_iter run #6: crashed: INFO: rcu detected stall in ext4_file_write_iter run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in ext4_file_write_iter run #9: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good e764a1e32337aaf325fc5b14a5bbd06eabba4699 Bisecting: 858 revisions left to test after this (roughly 10 steps) [f320ac6e131669345c7f4abefbb228b570eb9199] Merge branch 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs testing commit f320ac6e131669345c7f4abefbb228b570eb9199 with gcc (GCC) 8.1.0 kernel signature: eafa2ec8ef3aaf86206d06846079f3914ef5543e63643350fb79bed6a7fe1cca all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good f320ac6e131669345c7f4abefbb228b570eb9199 Bisecting: 427 revisions left to test after this (roughly 9 steps) [b765a32a2e9170702467747e290614be072c4f76] Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi testing commit b765a32a2e9170702467747e290614be072c4f76 with gcc (GCC) 8.1.0 kernel signature: 5fbe9aa7b8e411599fefdfbe69f74e6ea1f56b9b657eef3259b2d713b7947a47 run #0: crashed: INFO: rcu detected stall in ext4_file_write_iter run #1: crashed: INFO: rcu detected stall in ext4_file_write_iter run #2: crashed: INFO: rcu detected stall in corrupted run #3: crashed: INFO: rcu detected stall in ext4_file_write_iter run #4: crashed: INFO: rcu detected stall in ext4_file_write_iter run #5: crashed: INFO: rcu detected stall in ext4_file_write_iter run #6: crashed: INFO: rcu detected stall in ext4_file_write_iter run #7: crashed: INFO: rcu detected stall in ext4_file_write_iter run #8: crashed: INFO: rcu detected stall in ext4_file_write_iter run #9: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good b765a32a2e9170702467747e290614be072c4f76 Bisecting: 213 revisions left to test after this (roughly 8 steps) [428fc0aff4e59399ec719ffcc1f7a5d29a4ee476] include/linux/log2.h: add missing () around n in roundup_pow_of_two() testing commit 428fc0aff4e59399ec719ffcc1f7a5d29a4ee476 with gcc (GCC) 8.1.0 kernel signature: db78c61faf955732be5dfe7fa430722c4bca6ad0f1a076986e71d3b97f9964f7 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 428fc0aff4e59399ec719ffcc1f7a5d29a4ee476 Bisecting: 102 revisions left to test after this (roughly 7 steps) [f162626a038ec06da98ac38ce3d6bdbd715e9c5f] Merge tag 'pm-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm testing commit f162626a038ec06da98ac38ce3d6bdbd715e9c5f with gcc (GCC) 8.1.0 kernel signature: beff07a8b1f2976e900c5f05c2bbfa7ce5eabc1d05cf4d8e70c84bbec6034dcd all runs: OK # git bisect bad f162626a038ec06da98ac38ce3d6bdbd715e9c5f Bisecting: 54 revisions left to test after this (roughly 6 steps) [86edf52e7c7201fabfba39ae694a5206d48e77af] Merge tag 'sound-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound testing commit 86edf52e7c7201fabfba39ae694a5206d48e77af with gcc (GCC) 8.1.0 kernel signature: 16f38534f27e00b62d20da1afabbc0dae4707e74d87b9ec7c4f6aeb41981fa35 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 86edf52e7c7201fabfba39ae694a5206d48e77af Bisecting: 33 revisions left to test after this (roughly 5 steps) [7e24969022cbd61ddc586f14824fc205661bb124] block: allow for_each_bvec to support zero len bvec testing commit 7e24969022cbd61ddc586f14824fc205661bb124 with gcc (GCC) 8.1.0 kernel signature: 952b16b1e318a449d36bd000a08e177f843efbc727dd520b608b2409538a31c3 all runs: OK # git bisect bad 7e24969022cbd61ddc586f14824fc205661bb124 Bisecting: 10 revisions left to test after this (roughly 3 steps) [7cd49f7576b0c61d6c4a2114cda08cc4d5ce0028] nvme: Fix NULL dereference for pci nvme controllers testing commit 7cd49f7576b0c61d6c4a2114cda08cc4d5ce0028 with gcc (GCC) 8.1.0 kernel signature: 82f4f8a559b6fefb9b92f13ac82a940a016a8fc7e1ac778ebc5ff0b3580e3324 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 7cd49f7576b0c61d6c4a2114cda08cc4d5ce0028 Bisecting: 5 revisions left to test after this (roughly 3 steps) [5d220bcd378a1de14b9609c2706e041ba62253b6] Merge branch 'nvme-5.9-rc' of git://git.infradead.org/nvme into block-5.9 testing commit 5d220bcd378a1de14b9609c2706e041ba62253b6 with gcc (GCC) 8.1.0 kernel signature: e973c31ebc24eeb9216fd16bad7c0fd287297572ab712ec00fb97b5a3dcdce46 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 5d220bcd378a1de14b9609c2706e041ba62253b6 Bisecting: 2 revisions left to test after this (roughly 2 steps) [08fc1ab6d748ab1a690fd483f41e2938984ce353] block: fix locking in bdev_del_partition testing commit 08fc1ab6d748ab1a690fd483f41e2938984ce353 with gcc (GCC) 8.1.0 kernel signature: e388fced7ece68d1618467a3385e1a1d52497280b177c4417b0aa76e4cd732f9 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good 08fc1ab6d748ab1a690fd483f41e2938984ce353 Bisecting: 0 revisions left to test after this (roughly 1 step) [e11d80a849e010f78243bb6f6af7dccef3a71a90] blk-stat: make q->stats->lock irqsafe testing commit e11d80a849e010f78243bb6f6af7dccef3a71a90 with gcc (GCC) 8.1.0 kernel signature: 7969eb2ce03924d07c2118ffdf20e0be6a363f93d714e51f5b5f7d7fa54d3a65 all runs: crashed: INFO: rcu detected stall in ext4_file_write_iter # git bisect good e11d80a849e010f78243bb6f6af7dccef3a71a90 7e24969022cbd61ddc586f14824fc205661bb124 is the first bad commit commit 7e24969022cbd61ddc586f14824fc205661bb124 Author: Ming Lei Date: Mon Aug 17 18:00:55 2020 +0800 block: allow for_each_bvec to support zero len bvec Block layer usually doesn't support or allow zero-length bvec. Since commit 1bdc76aea115 ("iov_iter: use bvec iterator to implement iterate_bvec()"), iterate_bvec() switches to bvec iterator. However, Al mentioned that 'Zero-length segments are not disallowed' in iov_iter. Fixes for_each_bvec() so that it can move on after seeing one zero length bvec. Fixes: 1bdc76aea115 ("iov_iter: use bvec iterator to implement iterate_bvec()") Reported-by: syzbot Signed-off-by: Ming Lei Tested-by: Tetsuo Handa Cc: Al Viro Cc: Matthew Wilcox Cc: Link: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2262077.html Signed-off-by: Jens Axboe include/linux/bvec.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) culprit signature: 952b16b1e318a449d36bd000a08e177f843efbc727dd520b608b2409538a31c3 parent signature: 7969eb2ce03924d07c2118ffdf20e0be6a363f93d714e51f5b5f7d7fa54d3a65 revisions tested: 15, total time: 2h51m2.863804621s (build: 1h13m53.97514423s, test: 1h35m36.301616207s) first good commit: 7e24969022cbd61ddc586f14824fc205661bb124 block: allow for_each_bvec to support zero len bvec recipients (to): ["axboe@kernel.dk" "ming.lei@redhat.com" "penguin-kernel@i-love.sakura.ne.jp"] recipients (cc): []