On Tue, Mar 24, 2026 at 02:40:31PM +0100, Jan Kara wrote:
On Tue 24-03-26 08:34:47, Francesco Dolcini wrote:
I have an ext4 Oops on arm
[ 27.908560] 8<--- cut here --- [ 27.911697] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 27.919880] [00000000] *pgd=00000000 [ 27.923482] Internal error: Oops: 5 [#1] SMP ARM [ 27.928117] Modules linked in: 8021q cfg80211 imx_sdma coda_vpu v4l2_jpeg imx_vdoa dw_hdmi_ahb_audio fuse [ 27.937784] CPU: 1 PID: 736 Comm: tar Not tainted 6.1.167-rc1-6.8.6-devel+git.67c872a868ac #1 [ 27.946342] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 27.952889] PC is at ext4_mb_load_buddy_gfp+0xac/0x438
Can you run this through "addr2line -i" to get exact position in that big function? Because from a quick look it doesn't ring a bell...
I have a bisect for an ext4 issue in v6.1 which comes out at:
# first bad commit: [29897d75d6491ffe23cdc9d96caba9282a20dfc3] ext4: convert bd_bitmap_page to bd_bitmap_folio
For an oops which looks very similar (but on arm64):
[ 217.347067] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
...
[ 217.567412] Call trace: [ 217.569884] ext4_mb_load_buddy_gfp (include/asm-generic/bitops/generic-non-atomic.h:128 include/linux/page-flags.h:719 fs/ext4/mballoc.c:1536) [ 217.574388] ext4_discard_preallocations (fs/ext4/mballoc.c:5137) [ 217.579421] ext4_release_file (fs/ext4/file.c:167 (discriminator 1)) [ 217.583396] __fput (fs/file_table.c:321 (discriminator 1)) [ 217.586490] ____fput (fs/file_table.c:349) [ 217.589671] task_work_run (kernel/task_work.c:206 (discriminator 1)) [ 217.593294] do_notify_resume (include/linux/resume_user_mode.h:49 arch/arm64/kernel/signal.c:1151) [ 217.597358] el0_svc (arch/arm64/kernel/entry-common.c:639) [ 217.600452] el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:656) [ 217.604866] el0t_64_sync (arch/arm64/kernel/entry.S:585)
Full log:
https://lava.sirena.org.uk/scheduler/job/2595460#L3223
vmlinux:
https://builds.sirena.org.uk/67c872a868ac98d7af3b5598c399eec173c1eb03/arm64/...
Full bisect log:
# bad: [67c872a868ac98d7af3b5598c399eec173c1eb03] Linux 6.1.167-rc1 # good: [f2ddafa93a259310ca47507153b7811ec54ab7fd] Linux 6.1.166 git bisect start '67c872a868ac98d7af3b5598c399eec173c1eb03' 'f2ddafa93a259310ca47507153b7811ec54ab7fd' # test job: [67c872a868ac98d7af3b5598c399eec173c1eb03] https://lava.sirena.org.uk/scheduler/job/2595460 # bad: [67c872a868ac98d7af3b5598c399eec173c1eb03] Linux 6.1.167-rc1 git bisect bad 67c872a868ac98d7af3b5598c399eec173c1eb03 # test job: [19577ea2af78e1668d2dd7dd8ff49329363c8de6] https://lava.sirena.org.uk/scheduler/job/2596565 # bad: [19577ea2af78e1668d2dd7dd8ff49329363c8de6] parisc: Increase initial mapping to 64 MB with KALLSYMS git bisect bad 19577ea2af78e1668d2dd7dd8ff49329363c8de6 # test job: [525e916e0f088809ef9111088480f7271d0c63cb] https://lava.sirena.org.uk/scheduler/job/2596655 # bad: [525e916e0f088809ef9111088480f7271d0c63cb] octeon_ep: avoid compiler and IQ/OQ reordering git bisect bad 525e916e0f088809ef9111088480f7271d0c63cb # test job: [be91f915a7a7e3c089fe5edaaae047dfed585492] https://lava.sirena.org.uk/scheduler/job/2596752 # bad: [be91f915a7a7e3c089fe5edaaae047dfed585492] usb: cdns3: remove redundant if branch git bisect bad be91f915a7a7e3c089fe5edaaae047dfed585492 # test job: [7aaacb29d6420a3d9b09386545ee2d3afb5df5f3] https://lava.sirena.org.uk/scheduler/job/2596861 # good: [7aaacb29d6420a3d9b09386545ee2d3afb5df5f3] media: tegra-video: Use accessors for pad config 'try_*' fields git bisect good 7aaacb29d6420a3d9b09386545ee2d3afb5df5f3 # test job: [d21133e5855b8a332718992df631a151276b3a93] https://lava.sirena.org.uk/scheduler/job/2596893 # good: [d21133e5855b8a332718992df631a151276b3a93] ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 git bisect good d21133e5855b8a332718992df631a151276b3a93 # test job: [fe80bba8f76f9f0995cdc64fc89b65173e1ae828] https://lava.sirena.org.uk/scheduler/job/2596923 # bad: [fe80bba8f76f9f0995cdc64fc89b65173e1ae828] ext4: convert bd_buddy_page to bd_buddy_folio git bisect bad fe80bba8f76f9f0995cdc64fc89b65173e1ae828 # test job: [b41ad91ef08bd65607929c01da58a745c52f099a] https://lava.sirena.org.uk/scheduler/job/2596982 # good: [b41ad91ef08bd65607929c01da58a745c52f099a] ext4: remove unnecessary e4b->bd_buddy_page check in ext4_mb_load_buddy_gfp git bisect good b41ad91ef08bd65607929c01da58a745c52f099a # test job: [500bdda4b7db98fc1f979670924696d7ce449124] https://lava.sirena.org.uk/scheduler/job/2597035 # good: [500bdda4b7db98fc1f979670924696d7ce449124] ext4: delete redundant calculations in ext4_mb_get_buddy_page_lock() git bisect good 500bdda4b7db98fc1f979670924696d7ce449124 # test job: [29897d75d6491ffe23cdc9d96caba9282a20dfc3] https://lava.sirena.org.uk/scheduler/job/2597064 # bad: [29897d75d6491ffe23cdc9d96caba9282a20dfc3] ext4: convert bd_bitmap_page to bd_bitmap_folio git bisect bad 29897d75d6491ffe23cdc9d96caba9282a20dfc3 # first bad commit: [29897d75d6491ffe23cdc9d96caba9282a20dfc3] ext4: convert bd_bitmap_page to bd_bitmap_folio