hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ICCT8Z CVE: NA -------------------------------- Commit deb2d2ecd43df ("PCI/GPU: implement VGA arbitration on Linux") In the vga_arb_release(), it iterates through the vga_arb_user_card array held by the user to release io_cnt and mem_cnt resources one by one. If the values of io_cnt or mem_cnt are excessively large, prolonged CPU occupation may occur, leading to hard lock. lock protection is only added when deleting entries from the list, also add cond_resched() during the release of io_cnt and mem_cnt. Fixes: 9c7af565c58e ("centos 8.1: import linux-4.18.0-147.5.1.el8_1") Reviewed-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zhang Yuwei <zhangyuwei20@huawei.com> --- drivers/gpu/vga/vgaarb.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c index c61b04555779..db21ae342bd8 100644 --- a/drivers/gpu/vga/vgaarb.c +++ b/drivers/gpu/vga/vgaarb.c @@ -1312,18 +1312,22 @@ static int vga_arb_release(struct inode *inode, struct file *file) spin_lock_irqsave(&vga_user_lock, flags); list_del(&priv->list); + spin_unlock_irqrestore(&vga_user_lock, flags); for (i = 0; i < MAX_USER_CARDS; i++) { uc = &priv->cards[i]; if (uc->pdev == NULL) continue; vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", uc->io_cnt, uc->mem_cnt); - while (uc->io_cnt--) + while (uc->io_cnt--) { vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); - while (uc->mem_cnt--) + cond_resched(); + } + while (uc->mem_cnt--) { vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); + cond_resched(); + } } - spin_unlock_irqrestore(&vga_user_lock, flags); kfree(priv); -- 2.22.0