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ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow
[ Upstream commitbc056e7163
] 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. Cc: stable@kernel.org # 6.4 Fixes:93cdf49f6e
("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20230724121059.11834-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org>
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1 changed files with 14 additions and 17 deletions
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@ -5177,8 +5177,11 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
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pa = ac->ac_pa;
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pa = ac->ac_pa;
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if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
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if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
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int new_bex_start;
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struct ext4_free_extent ex = {
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int new_bex_end;
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.fe_logical = ac->ac_g_ex.fe_logical,
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.fe_len = ac->ac_orig_goal_len,
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};
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loff_t orig_goal_end = extent_logical_end(sbi, &ex);
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/* we can't allocate as much as normalizer wants.
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/* we can't allocate as much as normalizer wants.
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* so, found space must get proper lstart
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* so, found space must get proper lstart
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@ -5197,29 +5200,23 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
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* still cover original start
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* still cover original start
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* 3. Else, keep the best ex at start of original request.
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* 3. Else, keep the best ex at start of original request.
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*/
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*/
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new_bex_end = ac->ac_g_ex.fe_logical +
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ex.fe_len = ac->ac_b_ex.fe_len;
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EXT4_C2B(sbi, ac->ac_orig_goal_len);
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new_bex_start = new_bex_end - EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
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ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len);
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if (ac->ac_o_ex.fe_logical >= new_bex_start)
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if (ac->ac_o_ex.fe_logical >= ex.fe_logical)
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goto adjust_bex;
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goto adjust_bex;
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new_bex_start = ac->ac_g_ex.fe_logical;
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ex.fe_logical = ac->ac_g_ex.fe_logical;
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new_bex_end =
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if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
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new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
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if (ac->ac_o_ex.fe_logical < new_bex_end)
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goto adjust_bex;
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goto adjust_bex;
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new_bex_start = ac->ac_o_ex.fe_logical;
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ex.fe_logical = ac->ac_o_ex.fe_logical;
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new_bex_end =
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new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
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adjust_bex:
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adjust_bex:
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ac->ac_b_ex.fe_logical = new_bex_start;
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ac->ac_b_ex.fe_logical = ex.fe_logical;
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BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
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BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
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BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
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BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
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BUG_ON(new_bex_end > (ac->ac_g_ex.fe_logical +
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BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
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EXT4_C2B(sbi, ac->ac_orig_goal_len)));
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}
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}
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pa->pa_lstart = ac->ac_b_ex.fe_logical;
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pa->pa_lstart = ac->ac_b_ex.fe_logical;
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