When erofs_kill_sb() is called in block dev based mode, s_bdev may not have been initialised yet, and if CONFIG_EROFS_FS_ONDEMAND is enabled, it will be mistaken for fscache mode, and then attempt to free an anon_dev that has never been allocated, triggering the following warning:
============================================ ida_free called for id=0 which is not allocated. WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140 Modules linked in: CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty #630 RIP: 0010:ida_free+0x134/0x140 Call Trace: <TASK> erofs_kill_sb+0x81/0x90 deactivate_locked_super+0x35/0x80 get_tree_bdev+0x136/0x1e0 vfs_get_tree+0x2c/0xf0 do_new_mount+0x190/0x2f0 [...] ============================================ Instead of allocating the erofs_sb_info in fill_super() allocate it during erofs_get_tree() and ensure that erofs can always have the info available during erofs_kill_sb(). Signed-off-by: Christian Brauner <brau...@kernel.org> Signed-off-by: Baokun Li <libaok...@huawei.com> --- Changes since v1: Allocate and initialise fc->s_fs_info in erofs_fc_get_tree() instead of modifying fc->sb_flags. V1: https://lore.kernel.org/r/20240415121746.1207242-1-libaok...@huawei.com/ fs/erofs/super.c | 51 ++++++++++++++++++++++++++---------------------- 1 file changed, 28 insertions(+), 23 deletions(-) diff --git a/fs/erofs/super.c b/fs/erofs/super.c index b21bd8f78dc1..4104280be2ea 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -581,8 +581,7 @@ static const struct export_operations erofs_export_ops = { static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) { struct inode *inode; - struct erofs_sb_info *sbi; - struct erofs_fs_context *ctx = fc->fs_private; + struct erofs_sb_info *sbi = EROFS_SB(sb); int err; sb->s_magic = EROFS_SUPER_MAGIC; @@ -590,19 +589,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_op = &erofs_sops; - sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); - if (!sbi) - return -ENOMEM; - - sb->s_fs_info = sbi; - sbi->opt = ctx->opt; - sbi->devs = ctx->devs; - ctx->devs = NULL; - sbi->fsid = ctx->fsid; - ctx->fsid = NULL; - sbi->domain_id = ctx->domain_id; - ctx->domain_id = NULL; - sbi->blkszbits = PAGE_SHIFT; if (erofs_is_fscache_mode(sb)) { sb->s_blocksize = PAGE_SIZE; @@ -704,11 +690,32 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) return 0; } -static int erofs_fc_get_tree(struct fs_context *fc) +static void erofs_ctx_to_info(struct fs_context *fc) { struct erofs_fs_context *ctx = fc->fs_private; + struct erofs_sb_info *sbi = fc->s_fs_info; + + sbi->opt = ctx->opt; + sbi->devs = ctx->devs; + ctx->devs = NULL; + sbi->fsid = ctx->fsid; + ctx->fsid = NULL; + sbi->domain_id = ctx->domain_id; + ctx->domain_id = NULL; +} - if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->fsid) +static int erofs_fc_get_tree(struct fs_context *fc) +{ + struct erofs_sb_info *sbi; + + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); + if (!sbi) + return -ENOMEM; + + fc->s_fs_info = sbi; + erofs_ctx_to_info(fc); + + if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) return get_tree_nodev(fc, erofs_fc_fill_super); return get_tree_bdev(fc, erofs_fc_fill_super); @@ -767,6 +774,7 @@ static void erofs_fc_free(struct fs_context *fc) kfree(ctx->fsid); kfree(ctx->domain_id); kfree(ctx); + kfree(fc->s_fs_info); } static const struct fs_context_operations erofs_context_ops = { @@ -783,6 +791,7 @@ static int erofs_init_fs_context(struct fs_context *fc) ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; + ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL); if (!ctx->devs) { kfree(ctx); @@ -799,17 +808,13 @@ static int erofs_init_fs_context(struct fs_context *fc) static void erofs_kill_sb(struct super_block *sb) { - struct erofs_sb_info *sbi; + struct erofs_sb_info *sbi = EROFS_SB(sb); - if (erofs_is_fscache_mode(sb)) + if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) kill_anon_super(sb); else kill_block_super(sb); - sbi = EROFS_SB(sb); - if (!sbi) - return; - erofs_free_dev_context(sbi->devs); fs_put_dax(sbi->dax_dev, NULL); erofs_fscache_unregister_fs(sb); -- 2.31.1
