bisecting fixing commit since ee809c7e08956d737cb66454f5b6ca32cc0d9f26 building syzkaller on a60cb4cd840ce786236a00480e8bb1025e0c5fef testing commit ee809c7e08956d737cb66454f5b6ca32cc0d9f26 with gcc (GCC) 8.1.0 kernel signature: f21802887e937b2432da7fa5c55e6018b7ee0711 all runs: crashed: general protection fault in qdisc_destroy testing current HEAD fb683b5e3f53a73e761952735736180939a313df testing commit fb683b5e3f53a73e761952735736180939a313df with gcc (GCC) 8.1.0 kernel signature: 616069d58286978faf64ba128a9340065ff02e40 all runs: OK # git bisect start fb683b5e3f53a73e761952735736180939a313df ee809c7e08956d737cb66454f5b6ca32cc0d9f26 Bisecting: 1327 revisions left to test after this (roughly 10 steps) [6376736d016f71ed1d70ee0eb78583c8b29d0852] nvme-multipath: fix possible io hang after ctrl reconnect testing commit 6376736d016f71ed1d70ee0eb78583c8b29d0852 with gcc (GCC) 8.1.0 kernel signature: 18a63d61ca78ea485526482c60939d8e68bed5f0 all runs: OK # git bisect bad 6376736d016f71ed1d70ee0eb78583c8b29d0852 Bisecting: 663 revisions left to test after this (roughly 9 steps) [bbd76d9514c701d899f2c7255573ae0934bc3b9b] pktcdvd: remove warning on attempting to register non-passthrough dev testing commit bbd76d9514c701d899f2c7255573ae0934bc3b9b with gcc (GCC) 8.1.0 kernel signature: 80c61e708d84b63d7c6f7ebd3d81b815214e7fa1 all runs: OK # git bisect bad bbd76d9514c701d899f2c7255573ae0934bc3b9b Bisecting: 331 revisions left to test after this (roughly 8 steps) [5fdefdcb92bbedc16460a934e353702b546729b9] HID: Add quirk for HP X500 PIXART OEM mouse testing commit 5fdefdcb92bbedc16460a934e353702b546729b9 with gcc (GCC) 8.1.0 kernel signature: a926fa7dae3d0fc7207975f7eca1178ff4b1cde2 all runs: OK # git bisect bad 5fdefdcb92bbedc16460a934e353702b546729b9 Bisecting: 165 revisions left to test after this (roughly 7 steps) [ecf99cdea02dcc792c27a52d1cf3e1c532551479] dm thin metadata: check if in fail_io mode when setting needs_check testing commit ecf99cdea02dcc792c27a52d1cf3e1c532551479 with gcc (GCC) 8.1.0 kernel signature: f440ac52a7e94f348db4a867ee776d8ed9927403 all runs: crashed: general protection fault in qdisc_destroy # git bisect good ecf99cdea02dcc792c27a52d1cf3e1c532551479 Bisecting: 82 revisions left to test after this (roughly 6 steps) [4fb95f299504eb953d4a4fe1c58c65f26b006980] phy: renesas: rcar-gen3-usb2: Disable clearing VBUS in over-current testing commit 4fb95f299504eb953d4a4fe1c58c65f26b006980 with gcc (GCC) 8.1.0 kernel signature: 5a22a87f2a5b0c9f3220509b3c4a4a869cf6565b all runs: crashed: general protection fault in qdisc_destroy # git bisect good 4fb95f299504eb953d4a4fe1c58c65f26b006980 Bisecting: 41 revisions left to test after this (roughly 5 steps) [60f0d449601d7c4c375ffd3083b4c65f0950288c] NFSv2: Fix eof handling testing commit 60f0d449601d7c4c375ffd3083b4c65f0950288c with gcc (GCC) 8.1.0 kernel signature: d9326bbf4b539d5cd65b25d99757c764fd1de6dc all runs: OK # git bisect bad 60f0d449601d7c4c375ffd3083b4c65f0950288c Bisecting: 20 revisions left to test after this (roughly 4 steps) [999f33c2438c27895e9798a783d3a2ac5156d78f] bus: ti-sysc: Simplify cleanup upon failures in sysc_probe() testing commit 999f33c2438c27895e9798a783d3a2ac5156d78f with gcc (GCC) 8.1.0 kernel signature: 649f8cb421c0468f48026dc636d4bd01a70f964c all runs: OK # git bisect bad 999f33c2438c27895e9798a783d3a2ac5156d78f Bisecting: 9 revisions left to test after this (roughly 3 steps) [6a10e87ffca15ea2f5298890d84348855e219ea1] nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds testing commit 6a10e87ffca15ea2f5298890d84348855e219ea1 with gcc (GCC) 8.1.0 kernel signature: ac3b2e18a4bdc758d5a417fffa04a852bb5010a4 all runs: OK # git bisect bad 6a10e87ffca15ea2f5298890d84348855e219ea1 Bisecting: 4 revisions left to test after this (roughly 2 steps) [232a6462f43fceeac82bd99ef092b38e3a7ee296] KVM: coalesced_mmio: add bounds checking testing commit 232a6462f43fceeac82bd99ef092b38e3a7ee296 with gcc (GCC) 8.1.0 kernel signature: f44f5eaaadbe73e423d3d7cbac9101d6ade81118 all runs: OK # git bisect bad 232a6462f43fceeac82bd99ef092b38e3a7ee296 Bisecting: 2 revisions left to test after this (roughly 1 step) [fdd60d80c4294b7203d6f9d075a57da0a8d85fba] udp: correct reuseport selection with connected sockets testing commit fdd60d80c4294b7203d6f9d075a57da0a8d85fba with gcc (GCC) 8.1.0 kernel signature: 58d36ee437b16cfc1f7304256f626a102da57aac all runs: crashed: general protection fault in qdisc_destroy # git bisect good fdd60d80c4294b7203d6f9d075a57da0a8d85fba Bisecting: 0 revisions left to test after this (roughly 1 step) [7a1bad565cebfbf6956f9bb36dba734a48fa31d4] net_sched: let qdisc_put() accept NULL pointer testing commit 7a1bad565cebfbf6956f9bb36dba734a48fa31d4 with gcc (GCC) 8.1.0 kernel signature: f5edd23d59db5523e94d30a9fa9cb219ec6cd3bd all runs: OK # git bisect bad 7a1bad565cebfbf6956f9bb36dba734a48fa31d4 Bisecting: 0 revisions left to test after this (roughly 0 steps) [47288968eebd2fba3ee94a43d43934160cce1772] xen-netfront: do not assume sk_buff_head list is empty in error handling testing commit 47288968eebd2fba3ee94a43d43934160cce1772 with gcc (GCC) 8.1.0 kernel signature: 66c8f46130f942253a94410869d4fd2d26ebc52b all runs: crashed: general protection fault in qdisc_destroy # git bisect good 47288968eebd2fba3ee94a43d43934160cce1772 7a1bad565cebfbf6956f9bb36dba734a48fa31d4 is the first bad commit commit 7a1bad565cebfbf6956f9bb36dba734a48fa31d4 Author: Cong Wang Date: Thu Sep 12 10:22:30 2019 -0700 net_sched: let qdisc_put() accept NULL pointer [ Upstream commit 6efb971ba8edfbd80b666f29de12882852f095ae ] When tcf_block_get() fails in sfb_init(), q->qdisc is still a NULL pointer which leads to a crash in sfb_destroy(). Similar for sch_dsmark. Instead of fixing each separately, Linus suggested to just accept NULL pointer in qdisc_put(), which would make callers easier. (For sch_dsmark, the bug probably exists long before commit 6529eaba33f0.) Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure") Reported-by: syzbot+d5870a903591faaca4ae@syzkaller.appspotmail.com Suggested-by: Linus Torvalds Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Acked-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman net/sched/sch_generic.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) kernel signature: f5edd23d59db5523e94d30a9fa9cb219ec6cd3bd previous signature: 66c8f46130f942253a94410869d4fd2d26ebc52b revisions tested: 14, total time: 3h51m25.538027627s (build: 1h54m43.770545626s, test: 1h55m27.368280327s) first good commit: 7a1bad565cebfbf6956f9bb36dba734a48fa31d4 net_sched: let qdisc_put() accept NULL pointer cc: ["davem@davemloft.net" "gregkh@linuxfoundation.org" "jhs@mojatatu.com" "jiri@mellanox.com" "jiri@resnulli.us" "xiyou.wangcong@gmail.com"]