bisecting fixing commit since 7ae77150d94d3b535c7b85e6b3647113095e79bf building syzkaller on 54566aff1679fc74487d3efb9f7bbfbc21beed4b testing commit 7ae77150d94d3b535c7b85e6b3647113095e79bf with gcc (GCC) 8.1.0 kernel signature: 7ccc2428d1725437ba2ba25ae5b739f9ecb25565b1b9471f0084b14577b8e4b8 all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup testing current HEAD f804b3159482eedbb4250b1e9248c308fb63b805 testing commit f804b3159482eedbb4250b1e9248c308fb63b805 with gcc (GCC) 8.1.0 kernel signature: 96e726d62d7e8a9395e2c32919c0f1d3d6f19307f20e1f03af173a176be46bdf all runs: OK # git bisect start f804b3159482eedbb4250b1e9248c308fb63b805 7ae77150d94d3b535c7b85e6b3647113095e79bf Bisecting: 17874 revisions left to test after this (roughly 14 steps) [25d8d4eecace9de5a6a2193e4df1917afbdd3052] Merge tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux testing commit 25d8d4eecace9de5a6a2193e4df1917afbdd3052 with gcc (GCC) 8.1.0 kernel signature: 736ceec4160731ec366088617289274157d8cdc2feab352387c3ad434fc23e3b all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 25d8d4eecace9de5a6a2193e4df1917afbdd3052 Bisecting: 9032 revisions left to test after this (roughly 13 steps) [4815519ed0af833884ce9c288183bf1ae3cb9caa] Merge tag 'for-5.10/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm testing commit 4815519ed0af833884ce9c288183bf1ae3cb9caa with gcc (GCC) 8.1.0 kernel signature: 9e5dd3f845e81f75fc6ee8e28a7021091e7755249289fb8f5851202a1e94c587 all runs: OK # git bisect bad 4815519ed0af833884ce9c288183bf1ae3cb9caa Bisecting: 4426 revisions left to test after this (roughly 12 steps) [6c7247f6258b2dba353c885a1b00d795a380cc85] Merge tag 'staging-5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging testing commit 6c7247f6258b2dba353c885a1b00d795a380cc85 with gcc (GCC) 8.1.0 kernel signature: 671c16c009815b58746f5f49be707814ae53cdd8e89c9494aabc9d8913ec49da all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 6c7247f6258b2dba353c885a1b00d795a380cc85 Bisecting: 2168 revisions left to test after this (roughly 11 steps) [11e3235b4399f7e626caa791a68a0ea8337f6683] Merge tag 'for-5.10-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux testing commit 11e3235b4399f7e626caa791a68a0ea8337f6683 with gcc (GCC) 8.1.0 kernel signature: bd6791ffeb7f0d6c73dd8b45b045a0bf5a87c57eccdbd06cd5e4e587bfaa6596 all runs: OK # git bisect bad 11e3235b4399f7e626caa791a68a0ea8337f6683 Bisecting: 1100 revisions left to test after this (roughly 10 steps) [6734e20e39207556e17d72b5c4950d8f3a4f2de2] Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux testing commit 6734e20e39207556e17d72b5c4950d8f3a4f2de2 with gcc (GCC) 8.1.0 kernel signature: 9eaea9e126b0be3b08d2794a1a293c01be08c9000f1ad37c9705404c15fa232a all runs: OK # git bisect bad 6734e20e39207556e17d72b5c4950d8f3a4f2de2 Bisecting: 578 revisions left to test after this (roughly 9 steps) [eeddbe6841cde5524b0b1d01f6e060be564453bf] Merge tag 's390-5.9-7' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux testing commit eeddbe6841cde5524b0b1d01f6e060be564453bf with gcc (GCC) 8.1.0 kernel signature: af26308232c25d9b61323da8ab01d9ec823e7de88ec019319d686e485482e017 all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good eeddbe6841cde5524b0b1d01f6e060be564453bf Bisecting: 279 revisions left to test after this (roughly 8 steps) [165563c05088467e7e0ba382c5bdb04b6cbf0013] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net testing commit 165563c05088467e7e0ba382c5bdb04b6cbf0013 with gcc (GCC) 8.1.0 kernel signature: 9b7dbead9bb9ce967895e24a2c6e48f9a93f4c116f9ee5eaaba8fd9f2ff2631b all runs: OK # git bisect bad 165563c05088467e7e0ba382c5bdb04b6cbf0013 Bisecting: 149 revisions left to test after this (roughly 7 steps) [484cfaca95925f1a38ded6d0561de06a70409a32] mm, slub: restore initial kmem_cache flags testing commit 484cfaca95925f1a38ded6d0561de06a70409a32 with gcc (GCC) 8.1.0 kernel signature: 500376391e9a83339fec0dfff395bd1a30a26c741b14c793e06311e3649357fa all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 484cfaca95925f1a38ded6d0561de06a70409a32 Bisecting: 74 revisions left to test after this (roughly 6 steps) [be49b1ad299a638e6181aefc7bdbfd621b46a7ef] ice: preserve NVM capabilities in safe mode testing commit be49b1ad299a638e6181aefc7bdbfd621b46a7ef with gcc (GCC) 8.1.0 kernel signature: 48bb19cea68caafd0b364f89212f5509c0874e04c70c1800b2a20c8bd5c649d0 all runs: OK # git bisect bad be49b1ad299a638e6181aefc7bdbfd621b46a7ef Bisecting: 37 revisions left to test after this (roughly 5 steps) [72865028582a678be1e05240e55d452e5c258eca] mlxsw: spectrum_acl: Fix mlxsw_sp_acl_tcam_group_add()'s error path testing commit 72865028582a678be1e05240e55d452e5c258eca with gcc (GCC) 8.1.0 kernel signature: 727074d0ff6b3f490810874c8d6dc3e3ac74d9c7455f1a5788cabe80905d74fa all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 72865028582a678be1e05240e55d452e5c258eca Bisecting: 18 revisions left to test after this (roughly 4 steps) [9666ea66a74adfe295cb3a8760c76e1ef70f9caf] net: usb: ax88179_178a: fix missing stop entry in driver_info testing commit 9666ea66a74adfe295cb3a8760c76e1ef70f9caf with gcc (GCC) 8.1.0 kernel signature: 481fa36d98952c515c3d5321e1dd54f44b0d38e7b10eed424f028496532c4c90 all runs: OK # git bisect bad 9666ea66a74adfe295cb3a8760c76e1ef70f9caf Bisecting: 10 revisions left to test after this (roughly 3 steps) [e94ee171349db84c7cfdc5fefbebe414054d0924] xfrm: Use correct address family in xfrm_state_find testing commit e94ee171349db84c7cfdc5fefbebe414054d0924 with gcc (GCC) 8.1.0 kernel signature: 1a5a7c89aced046fa324e261bd8a23c08630ad4c727bb1046d5f8b845b30d0be all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good e94ee171349db84c7cfdc5fefbebe414054d0924 Bisecting: 5 revisions left to test after this (roughly 3 steps) [1aad8049909a6d3379175ef2824a68ac35c0b564] net_sched: remove a redundant goto chain check testing commit 1aad8049909a6d3379175ef2824a68ac35c0b564 with gcc (GCC) 8.1.0 kernel signature: 343f960eab61f43b19fdf89e91c51e785e2e26aa05092bd469dc5ef1c677594c all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 1aad8049909a6d3379175ef2824a68ac35c0b564 Bisecting: 2 revisions left to test after this (roughly 2 steps) [1fc70edb7d7b5ce1ae32b0cf90183f4879ad421a] net: core: add nested_level variable in net_device testing commit 1fc70edb7d7b5ce1ae32b0cf90183f4879ad421a with gcc (GCC) 8.1.0 kernel signature: e755e1e3998536e2ea631d36c20812c7f70b5f3f026d564a7f63a6106460f2d5 all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 1fc70edb7d7b5ce1ae32b0cf90183f4879ad421a Bisecting: 0 revisions left to test after this (roughly 1 step) [a7809ff90ce6c48598d3c4ab54eb599bec1e9c42] net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks testing commit a7809ff90ce6c48598d3c4ab54eb599bec1e9c42 with gcc (GCC) 8.1.0 kernel signature: bd6094a607be3ef9eda01296f15a5c6f9f813dc6a5159590aa5fef756094c49b all runs: OK # git bisect bad a7809ff90ce6c48598d3c4ab54eb599bec1e9c42 Bisecting: 0 revisions left to test after this (roughly 0 steps) [0ba56b89fabc139849cf27e475287b0361f550d3] Merge branch 'net-core-fix-a-lockdep-splat-in-the-dev_addr_list' testing commit 0ba56b89fabc139849cf27e475287b0361f550d3 with gcc (GCC) 8.1.0 kernel signature: e755e1e3998536e2ea631d36c20812c7f70b5f3f026d564a7f63a6106460f2d5 all runs: crashed: WARNING: suspicious RCU usage in ctrl_cmd_new_lookup # git bisect good 0ba56b89fabc139849cf27e475287b0361f550d3 a7809ff90ce6c48598d3c4ab54eb599bec1e9c42 is the first bad commit commit a7809ff90ce6c48598d3c4ab54eb599bec1e9c42 Author: Manivannan Sadhasivam Date: Sat Sep 26 22:26:25 2020 +0530 net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks The rcu read locks are needed to avoid potential race condition while dereferencing radix tree from multiple threads. The issue was identified by syzbot. Below is the crash report: ============================= WARNING: suspicious RCU usage 5.7.0-syzkaller #0 Not tainted ----------------------------- include/linux/radix-tree.h:176 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kworker/u4:1/21: #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2241 #1: ffffc90000dd7d80 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2243 stack backtrace: CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: qrtr_ns_handler qrtr_ns_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 radix_tree_deref_slot include/linux/radix-tree.h:176 [inline] ctrl_cmd_new_lookup net/qrtr/ns.c:558 [inline] qrtr_ns_worker+0x2aff/0x4500 net/qrtr/ns.c:674 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414 kthread+0x353/0x380 kernel/kthread.c:268 Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace") Reported-and-tested-by: syzbot+0f84f6eed90503da72fc@syzkaller.appspotmail.com Signed-off-by: Manivannan Sadhasivam Signed-off-by: David S. Miller net/qrtr/ns.c | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-) culprit signature: bd6094a607be3ef9eda01296f15a5c6f9f813dc6a5159590aa5fef756094c49b parent signature: e755e1e3998536e2ea631d36c20812c7f70b5f3f026d564a7f63a6106460f2d5 revisions tested: 18, total time: 3h43m17.041646776s (build: 1h46m8.660443224s, test: 1h54m26.67037926s) first good commit: a7809ff90ce6c48598d3c4ab54eb599bec1e9c42 net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks recipients (to): ["davem@davemloft.net" "manivannan.sadhasivam@linaro.org" "syzbot+0f84f6eed90503da72fc@syzkaller.appspotmail.com"] recipients (cc): []