Kernel panic with vFat mount

[hiroki363]

I use i.MX 8M Mini LPDDR4 EVK.

I use Linux 5.4.70_2.3.6(BSP).

I'm booting with eMMC.

When I insert the vFat USB stick, I get the following kernel panic.

--------------------

[ 1911.296573] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[ 1911.461156] usb-storage 1-1:1.0: USB Mass Storage device detected
[ 1911.468154] scsi host0: usb-storage 1-1:1.0
[ 1912.479225] scsi 0:0:0:0: Direct-Access BUFFALO USB Flash Disk 4000 PQ: 0 ANSI: 0 CCS
[ 1912.490919] sd 0:0:0:0: [sda] 4041728 512-byte logical blocks: (2.07 GB/1.93 GiB)
[ 1912.499167] sd 0:0:0:0: [sda] Write Protect is off
[ 1912.504658] sd 0:0:0:0: [sda] No Caching mode page found
[ 1912.510050] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 1912.643512] sda:
[ 1912.652791] sd 0:0:0:0: [sda] Attached SCSI removable disk
[ 1913.358298] sda:
[ 1913.438218] ------------[ cut here ]------------
[ 1913.442848] kernel BUG at arch/arm64/kernel/traps.c:405!
[ 1913.448165] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[ 1913.453652] Modules linked in: crct10dif_ce gpio_ir_recv rc_core
[ 1913.459666] CPU: 2 PID: 544 Comm: mount Not tainted 5.4.70-2.3.2+g5693275abe2a #1
[ 1913.467147] Hardware name: FSL i.MX8MM EVK board (DT)
[ 1913.472196] pstate: 00000005 (nzcv daif -PAN -UAO)
[ 1913.476993] pc : do_undefinstr+0x2e4/0x308
[ 1913.481087] lr : do_undefinstr+0x1d8/0x308
[ 1913.485180] sp : ffff800012053b30
[ 1913.488492] x29: ffff800012053b30 x28: ffff00007ad07000
[ 1913.493802] x27: 0000000000000000 x26: 0000000000000000
[ 1913.499111] x25: ffff800010382f20 x24: 0000000000000000
[ 1913.504421] x23: 0000000060000005 x22: ffff800010380720
[ 1913.509731] x21: ffff800012053cd0 x20: ffff00007ad07000
[ 1913.515042] x19: ffff800012053b90 x18: 0000000000000000
[ 1913.520352] x17: 0000000000000000 x16: 0000000000000000
[ 1913.525661] x15: ffffffffffffffff x14: 0000000000000000
[ 1913.530971] x13: 00000000000002a0 x12: 0000000000000020
[ 1913.536281] x11: 0101010101010101 x10: 0000000000000040
[ 1913.541592] x9 : 00000000fffffffe x8 : ffff00007b821bf0
[ 1913.546902] x7 : 0000000000000003 x6 : ffff800012053b88
[ 1913.552212] x5 : 00000000d5300000 x4 : ffff800011a14a10
[ 1913.557521] x3 : 0000000074700000 x2 : 0000000000000000
[ 1913.562831] x1 : ffff00007ad07000 x0 : 0000000060000005
[ 1913.568143] Call trace:
[ 1913.570590] do_undefinstr+0x2e4/0x308
[ 1913.574339] el1_undef+0x10/0x84
[ 1913.577568] fat_fill_super+0x0/0xc68
[ 1913.581230] mount_bdev+0x1a4/0x1d0
[ 1913.584717] vfat_mount+0x14/0x20
[ 1913.588032] legacy_get_tree+0x2c/0x58
[ 1913.591780] vfs_get_tree+0x24/0xe8
[ 1913.595268] do_mount+0x554/0x938
[ 1913.598582] ksys_mount+0x8c/0xe8
[ 1913.601896] __arm64_sys_mount+0x1c/0x28
[ 1913.605819] el0_svc_common.constprop.0+0x68/0x160
[ 1913.610608] el0_svc_handler+0x20/0x80
[ 1913.614355] el0_svc+0x8/0x208
[ 1913.617412] Code: f9401bf7 17ffff7d a9025bf5 f9001bf7 (d4210000)
[ 1913.623506] ---[ end trace 50fbefbfe78f1c91 ]---
[ 1913.628124] note: mount[544] exited with preempt_count 1
[ 1913.633989] ------------[ cut here ]------------
[ 1913.638626] WARNING: CPU: 2 PID: 0 at kernel/rcu/tree.c:569 rcu_idle_enter+0x78/0x80
[ 1913.646371] Modules linked in: crct10dif_ce gpio_ir_recv rc_core
[ 1913.652385] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G D 5.4.70-2.3.2+g5693275abe2a #1
[ 1913.661427] Hardware name: FSL i.MX8MM EVK board (DT)
[ 1913.666478] pstate: 200003c5 (nzCv DAIF -PAN -UAO)
[ 1913.671270] pc : rcu_idle_enter+0x78/0x80
[ 1913.675280] lr : do_idle+0x1d0/0x280
[ 1913.678853] sp : ffff800011c83f20
[ 1913.682165] x29: ffff800011c83f20 x28: 0000000000000000
[ 1913.687475] x27: 0000000000000000 x26: ffff00007ac9c000
[ 1913.692785] x25: ffff00007fba2c00 x24: ffff800011a09218
[ 1913.698094] x23: ffff00007a0aaa00 x22: ffff800011804bf8
[ 1913.703404] x21: ffff800011a091f0 x20: 0000000000000002
[ 1913.708717] x19: ffff800011a09118 x18: 0000000000000010
[ 1913.714025] x17: 0000000000000000 x16: 0000000000000000
[ 1913.719336] x15: 0000000000000073 x14: 0000000000000000
[ 1913.724646] x13: 0000000000000002 x12: 0000000000000073
[ 1913.729956] x11: 0000000000000001 x10: 000000000000089d
[ 1913.735267] x9 : ffff800011c83e80 x8 : ffff00007a0ab420
[ 1913.740577] x7 : 00000000000003fe x6 : 0000000392c65628
[ 1913.745887] x5 : 0000000000000dbb x4 : ffff80006e39e000
[ 1913.751198] x3 : 4000000000000002 x2 : 4000000000000000
[ 1913.756508] x1 : ffff800011808080 x0 : ffff00007fba6080
[ 1913.761818] Call trace:
[ 1913.764265] rcu_idle_enter+0x78/0x80
[ 1913.767924] do_idle+0x1d0/0x280
[ 1913.771151] cpu_startup_entry+0x20/0x80
[ 1913.775074] secondary_start_kernel+0x154/0x190
[ 1913.779603] ---[ end trace 50fbefbfe78f1c92 ]---

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When I insert the ext4 USB stick, there is no kernel panic.
Also, when the SD card is booted, the kernel panic does not occur even if the vFat USB memory is inserted.

Do you know what the cause is?

[Zhiming_Liu]

Can you try the L5.15.5 BSP? This issue could releate to kernel process schedule.