• Andrey Ryabinin's avatar
    stackdepot: respect __GFP_NOLOCKDEP allocation flag · 6fe60465
    Andrey Ryabinin authored
    If stack_depot_save_flags() allocates memory it always drops
    __GFP_NOLOCKDEP flag.  So when KASAN tries to track __GFP_NOLOCKDEP
    allocation we may end up with lockdep splat like bellow:
    
    ======================================================
     WARNING: possible circular locking dependency detected
     6.9.0-rc3+ #49 Not tainted
     ------------------------------------------------------
     kswapd0/149 is trying to acquire lock:
     ffff88811346a920
    (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_reclaim_inode+0x3ac/0x590
    [xfs]
    
     but task is already holding lock:
     ffffffff8bb33100 (fs_reclaim){+.+.}-{0:0}, at:
    balance_pgdat+0x5d9/0xad0
    
     which lock already depends on the new lock.
    
     the existing dependency chain (in reverse order) is:
     -> #1 (fs_reclaim){+.+.}-{0:0}:
            __lock_acquire+0x7da/0x1030
            lock_acquire+0x15d/0x400
            fs_reclaim_acquire+0xb5/0x100
     prepare_alloc_pages.constprop.0+0xc5/0x230
            __alloc_pages+0x12a/0x3f0
            alloc_pages_mpol+0x175/0x340
            stack_depot_save_flags+0x4c5/0x510
            kasan_save_stack+0x30/0x40
            kasan_save_track+0x10/0x30
            __kasan_slab_alloc+0x83/0x90
            kmem_cache_alloc+0x15e/0x4a0
            __alloc_object+0x35/0x370
            __create_object+0x22/0x90
     __kmalloc_node_track_caller+0x477/0x5b0
            krealloc+0x5f/0x110
            xfs_iext_insert_raw+0x4b2/0x6e0 [xfs]
            xfs_iext_insert+0x2e/0x130 [xfs]
            xfs_iread_bmbt_block+0x1a9/0x4d0 [xfs]
            xfs_btree_visit_block+0xfb/0x290 [xfs]
            xfs_btree_visit_blocks+0x215/0x2c0 [xfs]
            xfs_iread_extents+0x1a2/0x2e0 [xfs]
     xfs_buffered_write_iomap_begin+0x376/0x10a0 [xfs]
            iomap_iter+0x1d1/0x2d0
     iomap_file_buffered_write+0x120/0x1a0
            xfs_file_buffered_write+0x128/0x4b0 [xfs]
            vfs_write+0x675/0x890
            ksys_write+0xc3/0x160
            do_syscall_64+0x94/0x170
     entry_SYSCALL_64_after_hwframe+0x71/0x79
    
    Always preserve __GFP_NOLOCKDEP to fix this.
    
    Link: https://lkml.kernel.org/r/20240418141133.22950-1-ryabinin.a.a@gmail.com
    Fixes: cd11016e ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
    Signed-off-by: default avatarAndrey Ryabinin <ryabinin.a.a@gmail.com>
    Reported-by: default avatarXiubo Li <xiubli@redhat.com>
    Closes: https://lore.kernel.org/all/a0caa289-ca02-48eb-9bf2-d86fd47b71f4@redhat.com/Reported-by: default avatarDamien Le Moal <damien.lemoal@opensource.wdc.com>
    Closes: https://lore.kernel.org/all/f9ff999a-e170-b66b-7caf-293f2b147ac2@opensource.wdc.com/Suggested-by: default avatarDave Chinner <david@fromorbit.com>
    Tested-by: default avatarXiubo Li <xiubli@redhat.com>
    Cc: Christoph Hellwig <hch@infradead.org>
    Cc: Alexander Potapenko <glider@google.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    6fe60465
stackdepot.c 22.5 KB