FAILED: patch "[PATCH] ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x bc056e7163ac7db945366de219745cf94f32a3e6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023091643-excluding-lining-7075@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

bc056e7163ac ("ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow") 7e170922f06b ("ext4: Add allocation criteria 1.5 (CR1_5)")
1b4200112108 ("ext4: Avoid scanning smaller extents in BG during CR1") 3ef5d2638796 ("ext4: Add counter to track successful allocation of goal length") 4eb7a4a1a33b ("ext4: Convert mballoc cr (criteria) to enum")
c3defd99d58c ("ext4: treat stripe in block unit")
361eb69fc99f ("ext4: Remove the logic to trim inode PAs")
3872778664e3 ("ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list") a8e38fd37cff ("ext4: Convert pa->pa_inode_list and pa->pa_obj_lock into a union") 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") 0830344c953a ("ext4: Abstract out overlap fix/check logic in ext4_mb_normalize_request()") 7692094ac513 ("ext4: Move overlap assert logic into a separate function") bcf434992145 ("ext4: Refactor code in ext4_mb_normalize_request() and ext4_mb_use_preallocated()") e86a718228b6 ("ext4: Stop searching if PA doesn't satisfy non-extent file") 91a48aaf59d0 ("ext4: avoid unnecessary pointer dereference in ext4_mb_normalize_request") 83e80a6e3543 ("ext4: use buckets for cr 1 block scan instead of rbtree") 4fca50d440cc ("ext4: make mballoc try target group first even with mb_optimize_scan") cf4ff938b47f ("ext4: correct the judgment of BUG in ext4_mb_normalize_request") 359745d78351 ("proc: remove PDE_DATA() completely")
6dfbbae14a7b ("fs: proc: store PDE()->data into inode->i_private")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bc056e7163ac7db945366de219745cf94f32a3e6 Mon Sep 17 00:00:00 2001
From: Baokun Li <[email protected]>
Date: Mon, 24 Jul 2023 20:10:58 +0800
Subject: [PATCH] ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow

When we calculate the end position of ext4_free_extent, this position may be exactly where ext4_lblk_t (i.e. uint) overflows. For example, if ac_g_ex.fe_logical is 4294965248 and ac_orig_goal_len is 2048, then the computed end is 0x100000000, which is 0. If ac->ac_o_ex.fe_logical is not the first case of adjusting the best extent, that is, new_bex_end > 0, the following BUG_ON will be triggered:

=========================================================
kernel BUG at fs/ext4/mballoc.c:5116!
invalid opcode: 0000 [#1] PREEMPT SMP PTI

CPU: 3 PID: 673 Comm: xfs_io Tainted: G E 6.5.0-rc1+ #279
RIP: 0010:ext4_mb_new_inode_pa+0xc5/0x430
Call Trace:
 <TASK>
 ext4_mb_use_best_found+0x203/0x2f0
 ext4_mb_try_best_found+0x163/0x240
 ext4_mb_regular_allocator+0x158/0x1550
 ext4_mb_new_blocks+0x86a/0xe10
 ext4_ext_map_blocks+0xb0c/0x13a0
 ext4_map_blocks+0x2cd/0x8f0
 ext4_iomap_begin+0x27b/0x400
 iomap_iter+0x222/0x3d0
 __iomap_dio_rw+0x243/0xcb0
 iomap_dio_rw+0x16/0x80
=========================================================

A simple reproducer demonstrating the problem:

	mkfs.ext4 -F /dev/sda -b 4096 100M
	mount /dev/sda /tmp/test
	fallocate -l1M /tmp/test/tmp
	fallocate -l10M /tmp/test/file
	fallocate -i -o 1M -l16777203M /tmp/test/file
	fsstress -d /tmp/test -l 0 -n 100000 -p 8 &
	sleep 10 && killall -9 fsstress
	rm -f /tmp/test/tmp
	xfs_io -c "open -ad /tmp/test/file" -c "pwrite -S 0xff 0 8192"

We simply refactor the logic for adjusting the best extent by adding a temporary ext4_free_extent ex and use extent_logical_end() to avoid overflow, which also simplifies the code.

index 4cb13b3e41b3..86bce870dc5a 100644
@@ -5177,8 +5177,11 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 	pa = ac->ac_pa;
 
 	if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
-		int new_bex_start;
-		int new_bex_end;
+		struct ext4_free_extent ex = {
+			.fe_logical = ac->ac_g_ex.fe_logical,
+			.fe_len = ac->ac_orig_goal_len,
+		};
+		loff_t orig_goal_end = extent_logical_end(sbi, &ex);
 
 		/* we can't allocate as much as normalizer wants.
 		 * so, found space must get proper lstart

@@ -5197,29 +5200,23 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 		 *    still cover original start
 		 * 3. Else, keep the best ex at start of original request.
 		 */
-		new_bex_end = ac->ac_g_ex.fe_logical +
-			EXT4_C2B(sbi, ac->ac_orig_goal_len);
-		new_bex_start = new_bex_end - EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
-		if (ac->ac_o_ex.fe_logical >= new_bex_start)
-			goto adjust_bex;
+		ex.fe_len = ac->ac_b_ex.fe_len;
 
-		new_bex_start = ac->ac_g_ex.fe_logical;
-		new_bex_end =
-			new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
-		if (ac->ac_o_ex.fe_logical < new_bex_end)
+		ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len);
+		if (ac->ac_o_ex.fe_logical >= ex.fe_logical)
 			goto adjust_bex;
 
-		new_bex_start = ac->ac_o_ex.fe_logical;
-		new_bex_end =
-			new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+		ex.fe_logical = ac->ac_g_ex.fe_logical;
+		if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
+			goto adjust_bex;
 
+		ex.fe_logical = ac->ac_o_ex.fe_logical;
 adjust_bex:
-		ac->ac_b_ex.fe_logical = new_bex_start;
+		ac->ac_b_ex.fe_logical = ex.fe_logical;
 
 		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
 		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
-		BUG_ON(new_bex_end > (ac->ac_g_ex.fe_logical +
-				      EXT4_C2B(sbi, ac->ac_orig_goal_len)));
+		BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
 	}
 
 	pa->pa_lstart = ac->ac_b_ex.fe_logical;