bisecting fixing commit since ab9dfda232481dcfaf549ce774004d116fc80c13 building syzkaller on 8742a2b9dba1ce2869b29fff6c5359cc9116c719 testing commit ab9dfda232481dcfaf549ce774004d116fc80c13 with gcc (GCC) 8.1.0 kernel signature: 09c1c22a52d9315120f54ab7da1682be2aed133178b02195f5dc535a9d968c0c all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing current HEAD b850307b279cbd12ab8c654d1a3dfe55319cc475 testing commit b850307b279cbd12ab8c654d1a3dfe55319cc475 with gcc (GCC) 8.1.0 kernel signature: 2adc921fc2fba7dc6df7a2b5bca3d1cd321a6b5b0d429703dd0d9c722e121b9c all runs: OK # git bisect start b850307b279cbd12ab8c654d1a3dfe55319cc475 ab9dfda232481dcfaf549ce774004d116fc80c13 Bisecting: 149 revisions left to test after this (roughly 7 steps) [2b22a7419cfb5862919388954ef75e749dd9f813] l2tp: initialise PPP sessions before registering them testing commit 2b22a7419cfb5862919388954ef75e749dd9f813 with gcc (GCC) 8.1.0 kernel signature: 80dc300f17929a6b7f6691127005d2618d77b06e66febec15fc0389d8d32236f all runs: OK # git bisect bad 2b22a7419cfb5862919388954ef75e749dd9f813 Bisecting: 74 revisions left to test after this (roughly 6 steps) [1a99bcaa094d858bf90e67f4eff0e91797498018] gcc-10: disable 'zero-length-bounds' warning for now testing commit 1a99bcaa094d858bf90e67f4eff0e91797498018 with gcc (GCC) 8.1.0 kernel signature: a4c5bf3a57a9b024d699aed2599161e1d078d55b718c9e0aaad59a4e281cd97a all runs: OK # git bisect bad 1a99bcaa094d858bf90e67f4eff0e91797498018 Bisecting: 36 revisions left to test after this (roughly 5 steps) [081363a22ecd72ea1287a4ff0b539ba536c1b646] net: ipv6: add net argument to ip6_dst_lookup_flow testing commit 081363a22ecd72ea1287a4ff0b539ba536c1b646 with gcc (GCC) 8.1.0 kernel signature: 70434f661413dfef1b136f248ee71cad549f665f0806f3909cf256ce4c4ba35a all runs: OK # git bisect bad 081363a22ecd72ea1287a4ff0b539ba536c1b646 Bisecting: 18 revisions left to test after this (roughly 4 steps) [2079ed06852f392f7972b3c40dee8a5af05ddadf] HID: usbhid: Fix race between usbhid_close() and usbhid_stop() testing commit 2079ed06852f392f7972b3c40dee8a5af05ddadf with gcc (GCC) 8.1.0 kernel signature: e35ae38aaf779e2232150b382a608c78c45156a7769b19096d9964eed317b65a all runs: OK # git bisect bad 2079ed06852f392f7972b3c40dee8a5af05ddadf Bisecting: 8 revisions left to test after this (roughly 3 steps) [20d19a13f8c84e9dbd0a3a6b4c6988d8a57073cc] bnxt_en: Fix VLAN acceleration handling in bnxt_fix_features(). testing commit 20d19a13f8c84e9dbd0a3a6b4c6988d8a57073cc with gcc (GCC) 8.1.0 kernel signature: 8fb616e264bc3e18c80118077fae684229061179b0762bf8d78f89be5c1d5d1d all runs: OK # git bisect bad 20d19a13f8c84e9dbd0a3a6b4c6988d8a57073cc Bisecting: 4 revisions left to test after this (roughly 2 steps) [93f18b82d5e4a70fa79ed6d0eacf3858ddb219b3] net: macsec: preserve ingress frame ordering testing commit 93f18b82d5e4a70fa79ed6d0eacf3858ddb219b3 with gcc (GCC) 8.1.0 kernel signature: c4b3d8aedbeb0ad80f54dd3055e7a678b9065e7c6663899a97afcef4e6641968 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset # git bisect good 93f18b82d5e4a70fa79ed6d0eacf3858ddb219b3 Bisecting: 2 revisions left to test after this (roughly 1 step) [d6c0e9ea1c807a862ef29a0b52677fceb23226e5] net: usb: qmi_wwan: add support for DW5816e testing commit d6c0e9ea1c807a862ef29a0b52677fceb23226e5 with gcc (GCC) 8.1.0 kernel signature: 0f468d2393a24e2bc25ae2dda8540decf57967b87f2d88270b232a4724bafcf7 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset # git bisect good d6c0e9ea1c807a862ef29a0b52677fceb23226e5 Bisecting: 0 revisions left to test after this (roughly 1 step) [9945949908fe11b27fa1127d2fc9e3182c218312] sch_sfq: validate silly quantum values testing commit 9945949908fe11b27fa1127d2fc9e3182c218312 with gcc (GCC) 8.1.0 kernel signature: 865f39db07f645bf97f64a4a0cbd440474a86d8b90d2c94f91b50914f59e8ab7 all runs: OK # git bisect bad 9945949908fe11b27fa1127d2fc9e3182c218312 Bisecting: 0 revisions left to test after this (roughly 0 steps) [4836eb6b59657a383fa97d3d301da77581ec8f0c] sch_choke: avoid potential panic in choke_reset() testing commit 4836eb6b59657a383fa97d3d301da77581ec8f0c with gcc (GCC) 8.1.0 kernel signature: 11bf00ad1e3a86cdd209c7c7d496ff5155ba7dda7c89320a4e1ea43bbb4628d4 all runs: OK # git bisect bad 4836eb6b59657a383fa97d3d301da77581ec8f0c 4836eb6b59657a383fa97d3d301da77581ec8f0c is the first bad commit commit 4836eb6b59657a383fa97d3d301da77581ec8f0c Author: Eric Dumazet Date: Sat Apr 25 15:19:51 2020 -0700 sch_choke: avoid potential panic in choke_reset() [ Upstream commit 8738c85c72b3108c9b9a369a39868ba5f8e10ae0 ] If choke_init() could not allocate q->tab, we would crash later in choke_reset(). BUG: KASAN: null-ptr-deref in memset include/linux/string.h:366 [inline] BUG: KASAN: null-ptr-deref in choke_reset+0x208/0x340 net/sched/sch_choke.c:326 Write of size 8 at addr 0000000000000000 by task syz-executor822/7022 CPU: 1 PID: 7022 Comm: syz-executor822 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 __kasan_report.cold+0x5/0x4d mm/kasan/report.c:515 kasan_report+0x33/0x50 mm/kasan/common.c:625 check_memory_region_inline mm/kasan/generic.c:187 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:193 memset+0x20/0x40 mm/kasan/common.c:85 memset include/linux/string.h:366 [inline] choke_reset+0x208/0x340 net/sched/sch_choke.c:326 qdisc_reset+0x6b/0x520 net/sched/sch_generic.c:910 dev_deactivate_queue.constprop.0+0x13c/0x240 net/sched/sch_generic.c:1138 netdev_for_each_tx_queue include/linux/netdevice.h:2197 [inline] dev_deactivate_many+0xe2/0xba0 net/sched/sch_generic.c:1195 dev_deactivate+0xf8/0x1c0 net/sched/sch_generic.c:1233 qdisc_graft+0xd25/0x1120 net/sched/sch_api.c:1051 tc_modify_qdisc+0xbab/0x1a00 net/sched/sch_api.c:1670 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5454 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6bf/0x7e0 net/socket.c:2362 ___sys_sendmsg+0x100/0x170 net/socket.c:2416 __sys_sendmsg+0xec/0x1b0 net/socket.c:2449 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 Fixes: 77e62da6e60c ("sch_choke: drop all packets in queue during reset") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman net/sched/sch_choke.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) culprit signature: 11bf00ad1e3a86cdd209c7c7d496ff5155ba7dda7c89320a4e1ea43bbb4628d4 parent signature: 0f468d2393a24e2bc25ae2dda8540decf57967b87f2d88270b232a4724bafcf7 revisions tested: 11, total time: 3h6m59.674341969s (build: 1h30m27.945612688s, test: 1h34m58.035195136s) first good commit: 4836eb6b59657a383fa97d3d301da77581ec8f0c sch_choke: avoid potential panic in choke_reset() cc: ["davem@davemloft.net" "edumazet@google.com" "gregkh@linuxfoundation.org"]