ci starts bisection 2025-08-03 05:03:04.81819433 +0000 UTC m=+87392.363127281 bisecting fixing commit since 66701750d5565c574af42bef0b789ce0203e3071 building syzkaller on ffe4b334cb3673050f6078356393ce4b76adfc54 ensuring issue is reproducible on original commit 66701750d5565c574af42bef0b789ce0203e3071 testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 7ba91b72c34bb8e64af297da79770beb7469d974faa12db21ad1a36a4f9b694d all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] check whether we can drop unnecessary instrumentation disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 613092d8b8e126d9f0c5b74853d2927319b20002e14acd3969da9be77293a1c1 all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the bug reproduces without the instrumentation disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed kconfig minimization: base=4088 full=8356 leaves diff=2126 split chunks (needed=false): <2126> split chunk #0 of len 2126 into 5 parts testing without sub-chunk 1/5 disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: e0f5d22ab35165de34c79451dfee266789ba3f4427d411018126ba98bed80260 all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 7761e613c46a3e999c01fb05b39cf7dde3a74201e6bbd7723cfe80a900e71096 all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the chunk can be dropped testing without sub-chunk 3/5 disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 6fc5f97b70578d3de0747c8ea5cc621d14be9eb5bd5a5ddb239cdee93fd612cb all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the chunk can be dropped testing without sub-chunk 4/5 disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 59027cfbc9864a08770a67ae8fcf6af05065a3db3dfcc661e74cb5efbae5cf33 all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [bug_or_warning kasan locking atomic_sleep memleak ubsan], they are not needed testing commit 66701750d5565c574af42bef0b789ce0203e3071 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: d43e899ab54042378d2228616e84a411b7b83369376632e9fc0739da7f293e8b all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] the chunk can be dropped disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed testing current HEAD 186f3edfdd41f2ae87fc40a9ccba52a3bf930994 testing commit 186f3edfdd41f2ae87fc40a9ccba52a3bf930994 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 78915cc5dda15aafbf051d05a5b2f6a01f3ad7196fd153d7542e382ce1a5a740 all runs: OK false negative chance: 0.000 # git bisect start 186f3edfdd41f2ae87fc40a9ccba52a3bf930994 66701750d5565c574af42bef0b789ce0203e3071 Bisecting: 6835 revisions left to test after this (roughly 13 steps) [4b290aae788e06561754b28c6842e4080957d3f7] Merge tag 'sysctl-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit 4b290aae788e06561754b28c6842e4080957d3f7 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 48b611e52e13c60f7c711f90fbf643a4d3a1a397c87e5618f56c80c498487cc9 all runs: OK false negative chance: 0.000 # git bisect bad 4b290aae788e06561754b28c6842e4080957d3f7 Bisecting: 2764 revisions left to test after this (roughly 12 steps) [177bf8620cf4ed290ee170a6c5966adc0924b336] Merge tag 'sound-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit 177bf8620cf4ed290ee170a6c5966adc0924b336 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: e56a9a327125b3e90bce469b1beb5b3ea08b1493b8ee1a9eabf6f9fdee75413c all runs: OK false negative chance: 0.000 # git bisect bad 177bf8620cf4ed290ee170a6c5966adc0924b336 Bisecting: 1411 revisions left to test after this (roughly 11 steps) [76a9701325d39d8602695b19c49a9d0828c897ca] Merge tag 'erofs-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit 76a9701325d39d8602695b19c49a9d0828c897ca gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: c8ca75b175e8d9f4fb1ce69cd72392fd36bc07bd208569232ee9a3a147f9ffde all runs: OK false negative chance: 0.000 # git bisect bad 76a9701325d39d8602695b19c49a9d0828c897ca Bisecting: 707 revisions left to test after this (roughly 10 steps) [e6e82e5bedd7e924b670cea041d63aba1e03d06e] Merge tag 'pm-6.16-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit e6e82e5bedd7e924b670cea041d63aba1e03d06e gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: e90effce8239bb15de0157a9510ddacbab7d1811fed21fa98325db6757e8c800 all runs: OK false negative chance: 0.000 # git bisect bad e6e82e5bedd7e924b670cea041d63aba1e03d06e Bisecting: 330 revisions left to test after this (roughly 8 steps) [a1639ce5e590300af45bebedfbacf8fabc1777ed] Merge tag 'perf_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit a1639ce5e590300af45bebedfbacf8fabc1777ed gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 2eb4c672d20186ce6962e0eec3e2b514828c9f7e85cc653e3c690db82bf6fc96 all runs: OK false negative chance: 0.000 # git bisect bad a1639ce5e590300af45bebedfbacf8fabc1777ed Bisecting: 181 revisions left to test after this (roughly 7 steps) [923d401238c590f39833a2015f6f9493f146d98f] Merge tag 'iommu-fixes-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit 923d401238c590f39833a2015f6f9493f146d98f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: f8f6619dd982b8289cedd99a8364ab624ea15e83fe9992e23fea46eeaa3a5531 all runs: OK false negative chance: 0.000 # git bisect bad 923d401238c590f39833a2015f6f9493f146d98f Bisecting: 51 revisions left to test after this (roughly 6 steps) [17bbde2e1716e2ee4b997d476b48ae85c5a47671] Merge tag 'net-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net determine whether the revision contains the guilty commit revision 66701750d5565c574af42bef0b789ce0203e3071 crashed and is reachable testing commit 17bbde2e1716e2ee4b997d476b48ae85c5a47671 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: c71370d9bdb9c7eb5c111cf28cbd5e0f36cc45389dc24c3fd6940cf67fca94b7 all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] # git bisect good 17bbde2e1716e2ee4b997d476b48ae85c5a47671 Bisecting: 33 revisions left to test after this (roughly 5 steps) [1e7ab6f67824343ee3e96f100f0937c393749a8a] anon_inode: rework assertions determine whether the revision contains the guilty commit checking the merge base e04c78d86a9699d136910cfc0bdcf01087e3267e no existing result, test the revision testing commit e04c78d86a9699d136910cfc0bdcf01087e3267e gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 72f00a9aea06c463af2277c2270356fa710918d2b433938ecaaf42363682acfe all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] testing commit 1e7ab6f67824343ee3e96f100f0937c393749a8a gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 36b67c0680d5c4eafd24827af79e9539780a6ebf41a668cebd73fbcf6c8e0f68 all runs: OK false negative chance: 0.000 # git bisect bad 1e7ab6f67824343ee3e96f100f0937c393749a8a Bisecting: 8 revisions left to test after this (roughly 3 steps) [97d8e8e52cb8ab3d7675880a92626d9a4332f7a6] netfs: Fix ref leak on inserted extra subreq in write retry determine whether the revision contains the guilty commit revision e04c78d86a9699d136910cfc0bdcf01087e3267e crashed and is reachable testing commit 97d8e8e52cb8ab3d7675880a92626d9a4332f7a6 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: c455e482687cad41082089cd3bc9a0d023fb55e1368529a597333607e0e44b22 all runs: OK false negative chance: 0.000 # git bisect bad 97d8e8e52cb8ab3d7675880a92626d9a4332f7a6 Bisecting: 4 revisions left to test after this (roughly 2 steps) [8c44dac8add7503c345c0f6c7962e4863b88ba42] eventpoll: Fix priority inversion problem determine whether the revision contains the guilty commit revision e04c78d86a9699d136910cfc0bdcf01087e3267e crashed and is reachable testing commit 8c44dac8add7503c345c0f6c7962e4863b88ba42 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 187385282ba9855a8a2444141bdcac079be2ef91e32111c7a69779289008866e all runs: crashed: INFO: task hung in netfs_unbuffered_write_iter representative crash: INFO: task hung in netfs_unbuffered_write_iter, types: [HANG] # git bisect good 8c44dac8add7503c345c0f6c7962e4863b88ba42 Bisecting: 2 revisions left to test after this (roughly 1 step) [9df7b5ebead649b00bf9a53a798e4bf83a1318fd] netfs: Fix double put of request determine whether the revision contains the guilty commit revision 8c44dac8add7503c345c0f6c7962e4863b88ba42 crashed and is reachable testing commit 9df7b5ebead649b00bf9a53a798e4bf83a1318fd gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 failed building 9df7b5ebead649b00bf9a53a798e4bf83a1318fd: fs/netfs/misc.c:386:7: error: call to undeclared function 'netfs_check_rreq_in_progress'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] # git bisect skip 9df7b5ebead649b00bf9a53a798e4bf83a1318fd Bisecting: 1 revision left to test after this (roughly 1 step) [1a6d45fec33a03ca681eee125ea96987742a893f] netfs: Provide helpers to perform NETFS_RREQ_IN_PROGRESS flag wangling determine whether the revision contains the guilty commit revision 9df7b5ebead649b00bf9a53a798e4bf83a1318fd crashed and is reachable testing commit 1a6d45fec33a03ca681eee125ea96987742a893f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 994832aa5cb6da7f156874bc64021df8bf20665678f9c627a35dc3cc7bc48ce4 all runs: OK false negative chance: 0.000 # git bisect bad 1a6d45fec33a03ca681eee125ea96987742a893f Bisecting: 0 revisions left to test after this (roughly 1 step) [da8cf4bd458722d090a788c6e581eeb72695c62f] netfs: Fix hang due to missing case in final DIO read result collection determine whether the revision contains the guilty commit revision e04c78d86a9699d136910cfc0bdcf01087e3267e crashed and is reachable testing commit da8cf4bd458722d090a788c6e581eeb72695c62f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 3fcd4f233b505f335a10ed6a898514fb68fd679e10a59804a2f9bf35360624d1 all runs: OK false negative chance: 0.000 # git bisect bad da8cf4bd458722d090a788c6e581eeb72695c62f da8cf4bd458722d090a788c6e581eeb72695c62f is the first bad commit commit da8cf4bd458722d090a788c6e581eeb72695c62f Author: David Howells Date: Tue Jul 1 17:38:36 2025 +0100 netfs: Fix hang due to missing case in final DIO read result collection When doing a DIO read, if the subrequests we issue fail and cause the request PAUSE flag to be set to put a pause on subrequest generation, we may complete collection of the subrequests (possibly discarding them) prior to the ALL_QUEUED flags being set. In such a case, netfs_read_collection() doesn't see ALL_QUEUED being set after netfs_collect_read_results() returns and will just return to the app (the collector can be seen unpausing the generator in the trace log). The subrequest generator can then set ALL_QUEUED and the app thread reaches netfs_wait_for_request(). This causes netfs_collect_in_app() to be called to see if we're done yet, but there's missing case here. netfs_collect_in_app() will see that a thread is active and set inactive to false, but won't see any subrequests in the read stream, and so won't set need_collect to true. The function will then just return 0, indicating that the caller should just sleep until further activity (which won't be forthcoming) occurs. Fix this by making netfs_collect_in_app() check to see if an active thread is complete - i.e. that ALL_QUEUED is set and the subrequests list is empty - and to skip the sleep return path. The collector will then be called which will clear the request IN_PROGRESS flag, allowing the app to progress. Fixes: 2b1424cd131c ("netfs: Fix wait/wake to be consistent about the waitqueue used") Reported-by: Steve French Signed-off-by: David Howells Link: https://lore.kernel.org/20250701163852.2171681-2-dhowells@redhat.com Tested-by: Steve French Reviewed-by: Paulo Alcantara cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner fs/netfs/misc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) accumulated error probability: 0.00 culprit signature: 3fcd4f233b505f335a10ed6a898514fb68fd679e10a59804a2f9bf35360624d1 parent signature: 187385282ba9855a8a2444141bdcac079be2ef91e32111c7a69779289008866e revisions tested: 21, total time: 7h5m23.974327798s (build: 2h53m29.886922438s, test: 3h38m53.586886435s) first good commit: da8cf4bd458722d090a788c6e581eeb72695c62f netfs: Fix hang due to missing case in final DIO read result collection recipients (to): ["brauner@kernel.org" "dhowells@redhat.com" "pc@manguebit.org" "sfrench@samba.org"] recipients (cc): []