From 9cdd3128874f5fe759e2c4e1360ab7fb96a8d1df Mon Sep 17 00:00:00 2001 From: Baokun Li Date: Fri, 14 Jan 2022 18:28:54 +0800 Subject: [PATCH] jffs2: fix memory leak in jffs2_scan_medium If an error is returned in jffs2_scan_eraseblock() and some memory has been added to the jffs2_summary *s, we can observe the following kmemleak report: -------------------------------------------- unreferenced object 0xffff88812b889c40 (size 64): comm "mount", pid 692, jiffies 4294838325 (age 34.288s) hex dump (first 32 bytes): 40 48 b5 14 81 88 ff ff 01 e0 31 00 00 00 50 00 @H........1...P. 00 00 01 00 00 00 01 00 00 00 02 00 00 00 09 08 ................ backtrace: [] __kmalloc+0x613/0x910 [] jffs2_sum_add_dirent_mem+0x5c/0xa0 [] jffs2_scan_medium.cold+0x36e5/0x4794 [] jffs2_do_mount_fs.cold+0xa7/0x2267 [] jffs2_do_fill_super+0x383/0xc30 [] jffs2_fill_super+0x2ea/0x4c0 [] mtd_get_sb+0x254/0x400 [] mtd_get_sb_by_nr+0x4f/0xd0 [] get_tree_mtd+0x498/0x840 [] jffs2_get_tree+0x25/0x30 [] vfs_get_tree+0x8d/0x2e0 [] path_mount+0x50f/0x1e50 [] do_mount+0x107/0x130 [] __se_sys_mount+0x1c5/0x2f0 [] __x64_sys_mount+0xc7/0x160 [] do_syscall_64+0x45/0x70 unreferenced object 0xffff888114b54840 (size 32): comm "mount", pid 692, jiffies 4294838325 (age 34.288s) hex dump (first 32 bytes): c0 75 b5 14 81 88 ff ff 02 e0 02 00 00 00 02 00 .u.............. 00 00 84 00 00 00 44 00 00 00 6b 6b 6b 6b 6b a5 ......D...kkkkk. backtrace: [] kmem_cache_alloc_trace+0x584/0x880 [] jffs2_sum_add_inode_mem+0x54/0x90 [] jffs2_scan_medium.cold+0x4481/0x4794 [...] unreferenced object 0xffff888114b57280 (size 32): comm "mount", pid 692, jiffies 4294838393 (age 34.357s) hex dump (first 32 bytes): 10 d5 6c 11 81 88 ff ff 08 e0 05 00 00 00 01 00 ..l............. 00 00 38 02 00 00 28 00 00 00 6b 6b 6b 6b 6b a5 ..8...(...kkkkk. backtrace: [] kmem_cache_alloc_trace+0x584/0x880 [] jffs2_sum_add_xattr_mem+0x54/0x90 [] jffs2_scan_medium.cold+0x298c/0x4794 [...] unreferenced object 0xffff8881116cd510 (size 16): comm "mount", pid 692, jiffies 4294838395 (age 34.355s) hex dump (first 16 bytes): 00 00 00 00 00 00 00 00 09 e0 60 02 00 00 6b a5 ..........`...k. backtrace: [] kmem_cache_alloc_trace+0x584/0x880 [] jffs2_sum_add_xref_mem+0x54/0x90 [] jffs2_scan_medium.cold+0x3a20/0x4794 [...] -------------------------------------------- Therefore, we should call jffs2_sum_reset_collected(s) on exit to release the memory added in s. In addition, a new tag "out_buf" is added to prevent the NULL pointer reference caused by s being NULL. (thanks to Zhang Yi for this analysis) Fixes: e631ddba5887 ("[JFFS2] Add erase block summary support (mount time improvement)") Cc: stable@vger.kernel.org Co-developed-with: Zhihao Cheng Signed-off-by: Baokun Li Signed-off-by: Richard Weinberger --- fs/jffs2/scan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c index b676056826be..29671e33a171 100644 --- a/fs/jffs2/scan.c +++ b/fs/jffs2/scan.c @@ -136,7 +136,7 @@ int jffs2_scan_medium(struct jffs2_sb_info *c) if (!s) { JFFS2_WARNING("Can't allocate memory for summary\n"); ret = -ENOMEM; - goto out; + goto out_buf; } } @@ -275,13 +275,15 @@ int jffs2_scan_medium(struct jffs2_sb_info *c) } ret = 0; out: + jffs2_sum_reset_collected(s); + kfree(s); + out_buf: if (buf_size) kfree(flashbuf); #ifndef __ECOS else mtd_unpoint(c->mtd, 0, c->mtd->size); #endif - kfree(s); return ret; }