While booting stable rc 5.9.9-rc1 kernel on arm64 Qualcomm db410c device the following BUG: Invalid wait context noticed.

This issue has not reproduced after several testing loops.

[ 18.667840] [ 18.667865] ============================= [ 18.668392] [ BUG: Invalid wait context ] [ 18.672301] 5.9.9-rc1 #1 Not tainted [ 18.676291] ----------------------------- [ 18.679939] systemd-udevd/415 is trying to lock: [ 18.683846] ffff00003a73c718 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x60/0xa8 [ 18.688537] other info that might help us debug this: [ 18.696259] context-{4:4} [ 18.701379] 1 lock held by systemd-udevd/415: [ 18.703982] #0: ffff800012781a38 (rcu_read_lock){....}-{1:2}, at: xa_load+0x0/0x178 [ 18.708328] stack backtrace: [ 18.716137] CPU: 0 PID: 415 Comm: systemd-udevd Not tainted 5.9.9-rc1 #1 [ 18.719003] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) [ 18.725687] Call trace: [ 18.732369] dump_backtrace+0x0/0x1f8 [ 18.734540] show_stack+0x2c/0x38 [ 18.738360] dump_stack+0xec/0x158 [ 18.741658] __lock_acquire+0x520/0x1478 [ 18.744956] lock_acquire+0x120/0x4c8 [ 18.749035] __might_fault+0x84/0xa8 [ 18.752597] copy_page_to_iter+0xb4/0x3e8 [ 18.756242] generic_file_buffered_read+0x4bc/0xa98 [ 18.760148] generic_file_read_iter+0xd4/0x168 [ 18.764836] blkdev_read_iter+0x50/0x78 [ 18.769349] new_sync_read+0x100/0x1a0 [ 18.773082] vfs_read+0x1b4/0x1d8 [ 18.776900] ksys_read+0x74/0xf8 [ 18.780286] __arm64_sys_read+0x24/0x30 [ 18.783586] el0_svc_common.constprop.3+0x7c/0x198 [ 18.787143] do_el0_svc+0x34/0xa0 [ 18.792005] el0_sync_handler+0x16c/0x210 [ 18.795390] el0_sync+0x140/0x180

Reported-by: Naresh Kamboju naresh.kamboju@linaro.org

full test log details, https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-5.9.y/build/v5.9.8-... https://lkft.validation.linaro.org/scheduler/job/1951524#L4210

metadata: git branch: linux-5.9.y git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git git commit: fb1622495321923cbb1ae2c6cf2da1e9ca286800 git describe: v5.9.8-256-gfb1622495321 make_kernelversion: 5.9.9-rc1 kernel-config: http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/dragonboard-410c/lkf...