diff options
| author | Jiucheng Xu <jiucheng.xu@amlogic.com> | 2026-03-11 17:11:31 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 13:25:43 +0200 |
| commit | e83e20b82859f0588e9a52a6fa9fea704a2061cf (patch) | |
| tree | 30c49eaf7b2ef9807d9bd81c8bfae43134645449 /fs/erofs | |
| parent | 83ad334afc9a645cef1062f5346526b1e36d6516 (diff) | |
erofs: add GFP_NOIO in the bio completion if needed
commit c23df30915f83e7257c8625b690a1cece94142a0 upstream.
The bio completion path in the process context (e.g. dm-verity)
will directly call into decompression rather than trigger another
workqueue context for minimal scheduling latencies, which can
then call vm_map_ram() with GFP_KERNEL.
Due to insufficient memory, vm_map_ram() may generate memory
swapping I/O, which can cause submit_bio_wait to deadlock
in some scenarios.
Trimmed down the call stack, as follows:
f2fs_submit_read_io
submit_bio //bio_list is initialized.
mmc_blk_mq_recovery
z_erofs_endio
vm_map_ram
__pte_alloc_kernel
__alloc_pages_direct_reclaim
shrink_folio_list
__swap_writepage
submit_bio_wait //bio_list is non-NULL, hang!!!
Use memalloc_noio_{save,restore}() to wrap up this path.
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jiucheng Xu <jiucheng.xu@amlogic.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/erofs')
| -rw-r--r-- | fs/erofs/zdata.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index b71fcf4be484..8ba409df1ca7 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1459,6 +1459,7 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, int bios) { struct erofs_sb_info *const sbi = EROFS_SB(io->sb); + int gfp_flag; /* wake up the caller thread for sync decompression */ if (io->sync) { @@ -1491,7 +1492,9 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON; return; } + gfp_flag = memalloc_noio_save(); z_erofs_decompressqueue_work(&io->u.work); + memalloc_noio_restore(gfp_flag); } static void z_erofs_fill_bio_vec(struct bio_vec *bvec, |