[f2fs-dev] [Bug 220575] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

[bugzilla-daemon--- via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

https://bugzilla.kernel.org/show_bug.cgi?id=220575

--- Comment #11 from Chao Yu (chao@kernel.org) ---
(In reply to JY from comment #8)
> OK, I will try it.
> 
> At the last experiment, I used the newly added '_private' to record non-null
> value and dump it when fscrypt_is_bounce_page(page) is true.
> 
> +             pr_crit("bounced_page:0xpx, pp:0x%px,
> fscrypt_pagecache_page(page):0x%px\n", page, page->_private,
> fscrypt_pagecache_page(page));
> 
> The result is :
> bounced_page:0xfffffffe82282290, pp:0x0000000000000000,
> fscrypt_pagecache_page(page):0x0000000000000000
> (pp is page->_private)
> 
> I think the 'pp:0x0000000000000000' proves this page is not a bounce_page.
> Am I misunderstanding? :(
Can you please try below diff?

---
 fs/f2fs/data.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 1b0050b8421d..13bde4a2f40d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -884,6 +884,15 @@ void f2fs_submit_merged_ipu_write(struct f2fs_sb_info
*sbi,
        }
 }

+#define sanity_check_page(sbi, enc_page, page)                         \
+       do {                                                            \
+               if (page && !page->private) {                           \
+                       dump_page(enc_page, "dump enc_page");           \
+                       dump_page(page, "dump data page");              \
+                       BUG_ON(1);                                      \
+               }                                                       \
+       } while (0)
+
 int f2fs_merge_page_bio(struct f2fs_io_info *fio)
 {
        struct bio *bio = *fio->bio;
@@ -896,9 +905,13 @@ int f2fs_merge_page_bio(struct f2fs_io_info *fio)

        trace_f2fs_submit_page_bio(page, fio);

+       sanity_check_page(fio->sbi, fio->encrypted_page, fio->page);
+
        if (bio && !page_is_mergeable(fio->sbi, bio, *fio->last_block,
                                                fio->new_blkaddr))
                f2fs_submit_merged_ipu_write(fio->sbi, &bio, NULL);
+
+       sanity_check_page(fio->sbi, fio->encrypted_page, fio->page);
 alloc_new:
        if (!bio) {
                bio = __bio_alloc(fio, BIO_MAX_VECS);
@@ -906,15 +919,19 @@ int f2fs_merge_page_bio(struct f2fs_io_info *fio)
                                page_folio(fio->page)->index, fio, GFP_NOIO);

                add_bio_entry(fio->sbi, bio, page, fio->temp);
+               sanity_check_page(fio->sbi, fio->encrypted_page, fio->page);
        } else {
                if (add_ipu_page(fio, &bio, page))
                        goto alloc_new;
+               sanity_check_page(fio->sbi, fio->encrypted_page, fio->page);
        }

        if (fio->io_wbc)
                wbc_account_cgroup_owner(fio->io_wbc, page_folio(fio->page),
                                         PAGE_SIZE);

+       sanity_check_page(fio->sbi, fio->encrypted_page, fio->page);
+
        inc_page_count(fio->sbi, WB_DATA_TYPE(page, false));

        *fio->last_block = fio->new_blkaddr;
-- 
2.40.1

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are watching the assignee of the bug.

_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel