[PATCH] f2fs: vm_unmap_ram() may be called from an invalid context

[PATCH] f2fs: vm_unmap_ram() may be called from an invalid context

[Jan Prusakowski]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context.

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b (f2fs: handle decompress only post processing in softirq)

Signed-off-by: Jan Prusakowski <jprusakowski@google.com>
---
 fs/f2fs/data.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d1a2616d41be..0acc25f996b3 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -280,7 +280,7 @@ static void f2fs_read_end_io(struct bio *bio)
 {
 	struct f2fs_sb_info *sbi = F2FS_F_SB(bio_first_folio_all(bio));
 	struct bio_post_read_ctx *ctx;
-	bool intask = in_task();
+	bool intask = in_task() && !irqs_disabled();
 
 	iostat_update_and_unbind_ctx(bio);
 	ctx = bio->bi_private;
-- 
2.50.0.727.gbf7dc18ff4-goog

Re: [f2fs-dev] [PATCH] f2fs: vm_unmap_ram() may be called from an invalid context

[Chao Yu]

Jan,

On 2025/7/24 18:30, Jan Prusakowski via Linux-f2fs-devel wrote:
> When testing F2FS with xfstests using UFS backed virtual disks the
> kernel complains sometimes that f2fs_release_decomp_mem() calls
> vm_unmap_ram() from an invalid context.

It will be better to include testcase & crash information in commit
message.

> 
> This patch modifies in_task() check inside f2fs_read_end_io() to also
> check if interrupts are disabled. This ensures that pages are unmapped
> asynchronously in an interrupt handler.
> 
> Fixes: bff139b (f2fs: handle decompress only post processing in softirq)

./scripts/checkpatch.pl will output below warning message:

WARNING: Please use correct Fixes: style 'Fixes: <12+ chars of sha1> ("<title line>")' - ie: 'Fixes: bff139b49d9f ("f2fs: handle decompress only post processing in softirq")'

Please use this instead:

Fixes: bff139b49d9f ("f2fs: handle decompress only post processing in softirq")

> 
> Signed-off-by: Jan Prusakowski <jprusakowski@google.com>

Code part looks good to me, please feel free to add my RVB tag in next version:

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

> ---
>   fs/f2fs/data.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index d1a2616d41be..0acc25f996b3 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -280,7 +280,7 @@ static void f2fs_read_end_io(struct bio *bio)
>   {
>   	struct f2fs_sb_info *sbi = F2FS_F_SB(bio_first_folio_all(bio));
>   	struct bio_post_read_ctx *ctx;
> -	bool intask = in_task();
> +	bool intask = in_task() && !irqs_disabled();
>   
>   	iostat_update_and_unbind_ctx(bio);
>   	ctx = bio->bi_private;