bisecting cause commit starting from 3dbdb38e286903ec220aaf1fb29a8d94297da246
building syzkaller on 55aa55c24fe77aae07d530662f91b4d50c4990f0
testing commit 3dbdb38e286903ec220aaf1fb29a8d94297da246 with gcc (GCC) 10.2.1 20210217
kernel signature: 8481f9b2f2a7ab11d955c97afbc70c98b55326b531dbb64e72a19810026b3ae0
run #0: basic kernel testing failed: BUG: sleeping function called from invalid context in stack_depot_save
run #1: crashed: BUG: sleeping function called from invalid context in lock_sock_nested
run #2: crashed: possible deadlock in fs_reclaim_acquire
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
reproducer seems to be flaky
testing release v5.13
testing commit 62fb9874f5da54fdb243003b386128037319b219 with gcc (GCC) 10.2.1 20210217
kernel signature: b2b01d09ecb07ab9e2391336ffec13128978f4df5fdf36ea6198ee0e3ee4b360
run #0: crashed: BUG: sleeping function called from invalid context in lock_sock_nested
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
testing release v5.12
testing commit 9f4ad9e425a1d3b6a34617b8ea226d56a119a717 with gcc (GCC) 10.2.1 20210217
kernel signature: c0aa1dc77972e653d27b1131ed0a6e6fe8407d5227a7d01b1cbd0807e2bc6832
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: crashed: unregister_netdevice: waiting for DEV to become free
run #4: crashed: unregister_netdevice: waiting for DEV to become free
run #5: crashed: unregister_netdevice: waiting for DEV to become free
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
testing release v5.11
testing commit f40ddce88593482919761f74910f42f4b84c004b with gcc (GCC) 10.2.1 20210217
kernel signature: 59429d7110393b80e968a6073c424269fda16f0fb48472977ad8a8aa35716445
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
testing release v5.10
testing commit 2c85ebc57b3e1817b6ce1a6b703928e113a90442 with gcc (GCC) 10.2.1 20210217
kernel signature: 7514265c9e85742a3f4c15542d7efe97c68c310f00b1d803b2de34e4a535b0fb
all runs: OK
# git bisect start f40ddce88593482919761f74910f42f4b84c004b 2c85ebc57b3e1817b6ce1a6b703928e113a90442
Bisecting: 7761 revisions left to test after this (roughly 13 steps)
[538fcf57aaee6ad78a05f52b69a99baa22b33418] Merge branches 'acpi-scan', 'acpi-pnp' and 'acpi-sleep'

testing commit 538fcf57aaee6ad78a05f52b69a99baa22b33418 with gcc (GCC) 10.2.1 20210217
kernel signature: 579963c660bbfef9c8937fc6bacc744a0e936d63a98db3f748e33833fc8e74be
all runs: OK
# git bisect good 538fcf57aaee6ad78a05f52b69a99baa22b33418
Bisecting: 3868 revisions left to test after this (roughly 12 steps)
[d64c6f96ba86bd8b97ed8d6762a8c8cc1770d214] Merge tag 'net-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

testing commit d64c6f96ba86bd8b97ed8d6762a8c8cc1770d214 with gcc (GCC) 10.2.1 20210217
kernel signature: 6594f26b0cbb60700d4100e0f26efdb2fec1baa75a883d3b859b65facdf52543
all runs: OK
# git bisect good d64c6f96ba86bd8b97ed8d6762a8c8cc1770d214
Bisecting: 1934 revisions left to test after this (roughly 11 steps)
[70b6ff35d62050d1573876cc0e1e078acd3e6008] cfg80211/mac80211: fix kernel-doc for SAR APIs

testing commit 70b6ff35d62050d1573876cc0e1e078acd3e6008 with gcc (GCC) 10.2.1 20210217
kernel signature: 56ca8008c98ff85f3e5d943da55bf3c6747d5503d8a0231c342da6264a6f92b5
all runs: OK
# git bisect good 70b6ff35d62050d1573876cc0e1e078acd3e6008
Bisecting: 965 revisions left to test after this (roughly 10 steps)
[17b6c49da37f5d57d76bf352d32b0ac498e7c133] Merge tag 'x86_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 17b6c49da37f5d57d76bf352d32b0ac498e7c133 with gcc (GCC) 10.2.1 20210217
kernel signature: fd26e9bda8136ca89a520d51db7cd9f178b59c0f504939bf6bd1b9112d4daae0
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: crashed: unregister_netdevice: waiting for DEV to become free
run #4: crashed: unregister_netdevice: waiting for DEV to become free
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 17b6c49da37f5d57d76bf352d32b0ac498e7c133
Bisecting: 464 revisions left to test after this (roughly 9 steps)
[e8c13a6bc8ebbef7bd099ec1061633d1c9c94d5b] Merge tag 'net-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

testing commit e8c13a6bc8ebbef7bd099ec1061633d1c9c94d5b with gcc (GCC) 10.2.1 20210217
kernel signature: fa15f016ab1db22bb4c3f046d4ddc0c2563400ef8d6ebf2146718017ae49c3b8
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: crashed: unregister_netdevice: waiting for DEV to become free
run #4: crashed: unregister_netdevice: waiting for DEV to become free
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: crashed: unregister_netdevice: waiting for DEV to become free
run #17: OK
run #18: OK
run #19: OK
# git bisect bad e8c13a6bc8ebbef7bd099ec1061633d1c9c94d5b
Bisecting: 241 revisions left to test after this (roughly 8 steps)
[e07cd2f3e7e525fa8df334d11beceb4c1bdcc74e] Merge tag 'char-misc-5.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

testing commit e07cd2f3e7e525fa8df334d11beceb4c1bdcc74e with gcc (GCC) 10.2.1 20210217
kernel signature: 8e68ba3204d6d7507db6c49db6ddbd9a0a55b60ebbef9810448983adf43b6557
all runs: OK
# git bisect good e07cd2f3e7e525fa8df334d11beceb4c1bdcc74e
Bisecting: 126 revisions left to test after this (roughly 7 steps)
[ea49c88f4071e2bdd55e78987f251ea54aa11004] Merge tag 'mkp-scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi

testing commit ea49c88f4071e2bdd55e78987f251ea54aa11004 with gcc (GCC) 10.2.1 20210217
kernel signature: af06cd745119e0b68be8b20ca8d89c0f34a8519b8449b239e9fda7af3e31948d
all runs: OK
# git bisect good ea49c88f4071e2bdd55e78987f251ea54aa11004
Bisecting: 63 revisions left to test after this (roughly 6 steps)
[4f3786e011940d83d7a9c365730936db96a0b233] MAINTAINERS: ipvs: move Wensong Zhang to CREDITS

testing commit 4f3786e011940d83d7a9c365730936db96a0b233 with gcc (GCC) 10.2.1 20210217
kernel signature: ca3d5a54770d1f3240a7c66ad22a61a45bfdc289633abd5a79e21af6e6338c86
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: crashed: unregister_netdevice: waiting for DEV to become free
run #4: crashed: unregister_netdevice: waiting for DEV to become free
run #5: crashed: unregister_netdevice: waiting for DEV to become free
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: crashed: unregister_netdevice: waiting for DEV to become free
# git bisect bad 4f3786e011940d83d7a9c365730936db96a0b233
Bisecting: 30 revisions left to test after this (roughly 5 steps)
[ece9ab2a78afa1424c1aff45b1a95748dbc1f100] Merge branch 'bnxt_en-bug-fixes'

testing commit ece9ab2a78afa1424c1aff45b1a95748dbc1f100 with gcc (GCC) 10.2.1 20210217
kernel signature: 88508ebcef188b6320c90407bb119f2f84701bb2303d574669c26e843b121146
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: OK
run #4: crashed: unregister_netdevice: waiting for DEV to become free
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad ece9ab2a78afa1424c1aff45b1a95748dbc1f100
Bisecting: 15 revisions left to test after this (roughly 4 steps)
[f97844f9c518172f813b7ece18a9956b1f70c1bb] dt-bindings: net: renesas,etheravb: RZ/G2H needs tx-internal-delay-ps

testing commit f97844f9c518172f813b7ece18a9956b1f70c1bb with gcc (GCC) 10.2.1 20210217
kernel signature: c690db43bfae394c59b34ed05f6cf534c2625f688bc2e55aeea291c51769fe9d
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad f97844f9c518172f813b7ece18a9956b1f70c1bb
Bisecting: 7 revisions left to test after this (roughly 3 steps)
[c49243e8898233de18edfaaa5b7b261ea457f221] Merge branch 'net-fix-issues-around-register_netdevice-failures'

testing commit c49243e8898233de18edfaaa5b7b261ea457f221 with gcc (GCC) 10.2.1 20210217
kernel signature: cb04e19bc254bd1faf2a23f40bcb371800baf2a00c91cddc235505bc231fc156
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad c49243e8898233de18edfaaa5b7b261ea457f221
Bisecting: 3 revisions left to test after this (roughly 2 steps)
[c1787ffd0d24eb93eefac2dbba0eac5700da9ff1] ppp: fix refcount underflow on channel unbridge

testing commit c1787ffd0d24eb93eefac2dbba0eac5700da9ff1 with gcc (GCC) 10.2.1 20210217
kernel signature: 895011bf6106b7b3360585768702c69979c6d2382dbba417d6ad227a803ff557
all runs: OK
# git bisect good c1787ffd0d24eb93eefac2dbba0eac5700da9ff1
Bisecting: 1 revision left to test after this (roughly 1 step)
[c269a24ce057abfc31130960e96ab197ef6ab196] net: make free_netdev() more lenient with unregistering devices

testing commit c269a24ce057abfc31130960e96ab197ef6ab196 with gcc (GCC) 10.2.1 20210217
kernel signature: 558897da10873514c1566565d45f0f9c765fa1ef26a95d25f4583e96c1ac255d
all runs: OK
# git bisect good c269a24ce057abfc31130960e96ab197ef6ab196
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[766b0515d5bec4b780750773ed3009b148df8c0a] net: make sure devices go through netdev_wait_all_refs

testing commit 766b0515d5bec4b780750773ed3009b148df8c0a with gcc (GCC) 10.2.1 20210217
kernel signature: cb04e19bc254bd1faf2a23f40bcb371800baf2a00c91cddc235505bc231fc156
run #0: crashed: unregister_netdevice: waiting for DEV to become free
run #1: crashed: unregister_netdevice: waiting for DEV to become free
run #2: crashed: unregister_netdevice: waiting for DEV to become free
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 766b0515d5bec4b780750773ed3009b148df8c0a
766b0515d5bec4b780750773ed3009b148df8c0a is the first bad commit
commit 766b0515d5bec4b780750773ed3009b148df8c0a
Author: Jakub Kicinski <kuba@kernel.org>
Date:   Wed Jan 6 10:40:07 2021 -0800

    net: make sure devices go through netdev_wait_all_refs
    
    If register_netdevice() fails at the very last stage - the
    notifier call - some subsystems may have already seen it and
    grabbed a reference. struct net_device can't be freed right
    away without calling netdev_wait_all_refs().
    
    Now that we have a clean interface in form of dev->needs_free_netdev
    and lenient free_netdev() we can undo what commit 93ee31f14f6f ("[NET]:
    Fix free_netdev on register_netdev failure.") has done and complete
    the unregistration path by bringing the net_set_todo() call back.
    
    After registration fails user is still expected to explicitly
    free the net_device, so make sure ->needs_free_netdev is cleared,
    otherwise rolling back the registration will cause the old double
    free for callers who release rtnl_lock before the free.
    
    This also solves the problem of priv_destructor not being called
    on notifier error.
    
    net_set_todo() will be moved back into unregister_netdevice_queue()
    in a follow up.
    
    Reported-by: Hulk Robot <hulkci@huawei.com>
    Reported-by: Yang Yingliang <yangyingliang@huawei.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

 net/core/dev.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

culprit signature: cb04e19bc254bd1faf2a23f40bcb371800baf2a00c91cddc235505bc231fc156
parent  signature: 558897da10873514c1566565d45f0f9c765fa1ef26a95d25f4583e96c1ac255d
Reproducer flagged being flaky
revisions tested: 19, total time: 5h12m47.371148115s (build: 2h14m11.307427138s, test: 2h55m45.148374072s)
first bad commit: 766b0515d5bec4b780750773ed3009b148df8c0a net: make sure devices go through netdev_wait_all_refs
recipients (to): ["davem@davemloft.net" "kuba@kernel.org" "kuba@kernel.org" "netdev@vger.kernel.org"]
recipients (cc): ["andriin@fb.com" "ast@kernel.org" "linux-kernel@vger.kernel.org"]
crash: unregister_netdevice: waiting for DEV to become free
unregister_netdevice: waiting for sit0 to become free. Usage count = -1