| Message ID | 20180803055022.9816-7-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs-progs: Variant fixes for fuzz-tests | expand |
On 3.08.2018 08:50, Qu Wenruo wrote: > [BUG] > During fuzz/007 we hit the following error: > ------ > ====== RUN MAYFAIL /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch > ERROR: tree_root block unaligned: 33554431 > ERROR: superblock checksum matches but it has invalid members > ERROR: tree_root block unaligned: 33554431 > ERROR: superblock checksum matches but it has invalid members > ERROR: tree_root block unaligned: 33554431 > ERROR: superblock checksum matches but it has invalid members > ERROR: failed to add chunk map start=12582912 len=8454144: -17 (File exists) > Couldn't read chunk tree > failed (ignored, ret=139): /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch > mayfail: returned code 139 (SEGFAULT), not ignored > test failed for case 007-simple-super-recover > ------ > > [CAUSE] > In __open_ctree_fd(), if we have valid @open_ctree_flags and > btrfs_scan_fs_devices() successes without problem, no matter what > happens we will call btrfs_close_devices(), thus free all related > devices. Why do you think it's _always_ going to be called? Looking into that function it seems this can happen if btrfs_setup_chunk_tree_and_device_map fails. > > In super-recover, before we call open_ctree(), we have called > btrfs_scan_fs_devices() already, so btrfs_scan_fs_devices() should not > fail in open_ctree(), fs_devices will always be freed in open_ctree() or > close_ctree(). Isn't the actual issue just that we call close_ctree. So the actual life time of fs_devices is : 1. Create in btrfs_scan_fs_devices called from btrfs_recover_superblocks 2. All other references to those fs_devices will just return the same reference. 3. Calling close_ctree frees fs_devices. > > [FIX] > So in super-recover.c, we should not call btrfs_close_devices(), or we > will find fs_devices->list get poisoned, and trigger segfault when > exiting. > > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > super-recover.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/super-recover.c b/super-recover.c > index 880fd7712546..86b3df9867dc 100644 > --- a/super-recover.c > +++ b/super-recover.c > @@ -292,9 +292,6 @@ int btrfs_recover_superblocks(const char *dname, > no_recover: > recover_err_str(ret); > free_recover_superblock(&recover); > - /* check if we have freed fs_devices in close_ctree() */ > - if (!root) > - btrfs_close_devices(recover.fs_devices); > return ret; > } > >
On 2018/8/29 下午11:38, Nikolay Borisov wrote: > > > On 3.08.2018 08:50, Qu Wenruo wrote: >> [BUG] >> During fuzz/007 we hit the following error: >> ------ >> ====== RUN MAYFAIL /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch >> ERROR: tree_root block unaligned: 33554431 >> ERROR: superblock checksum matches but it has invalid members >> ERROR: tree_root block unaligned: 33554431 >> ERROR: superblock checksum matches but it has invalid members >> ERROR: tree_root block unaligned: 33554431 >> ERROR: superblock checksum matches but it has invalid members >> ERROR: failed to add chunk map start=12582912 len=8454144: -17 (File exists) >> Couldn't read chunk tree >> failed (ignored, ret=139): /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch >> mayfail: returned code 139 (SEGFAULT), not ignored >> test failed for case 007-simple-super-recover >> ------ >> >> [CAUSE] >> In __open_ctree_fd(), if we have valid @open_ctree_flags and >> btrfs_scan_fs_devices() successes without problem, no matter what >> happens we will call btrfs_close_devices(), thus free all related >> devices. > > Why do you think it's _always_ going to be called? Looking into that > function it seems this can happen if > btrfs_setup_chunk_tree_and_device_map fails. No need to reach btrfS_setup_chunk_tree_and_device_map(). As long as we could reach btrfs_open_devices(), no matter whether if succeeded or not, we will call btrfs_close_devices() to cleanup the @fs_devices. If btrfs_open_devices() fails, we goto fail label in btrfs_open_devices() which calls btrfs_close_devices(). Or we succeeded in btrfs_open_devices(), then next error label is out_devices in __open_ctree_fd(), and will call btrfs_close_devices() too. And since in super recovery we have already called btrfs_scan_fs_devices() so in __open_ctree_fd() it shouldn't fail. So either we will hit btrfs_close_devices(), no matter whatever happens. >> >> In super-recover, before we call open_ctree(), we have called >> btrfs_scan_fs_devices() already, so btrfs_scan_fs_devices() should not >> fail in open_ctree(), fs_devices will always be freed in open_ctree() or >> close_ctree(). > > Isn't the actual issue just that we call close_ctree. So the actual life > time of fs_devices is : No, no need to call close_ctree(). Just as described above, even failed __open_ctree_fd() could call btrfs_close_devices() and free @fs_devices. Thanks, Qu > > 1. Create in btrfs_scan_fs_devices called from btrfs_recover_superblocks > 2. All other references to those fs_devices will just return the same > reference. > 3. Calling close_ctree frees fs_devices. > >> >> [FIX] >> So in super-recover.c, we should not call btrfs_close_devices(), or we >> will find fs_devices->list get poisoned, and trigger segfault when >> exiting. >> >> Signed-off-by: Qu Wenruo <wqu@suse.com> >> --- >> super-recover.c | 3 --- >> 1 file changed, 3 deletions(-) >> >> diff --git a/super-recover.c b/super-recover.c >> index 880fd7712546..86b3df9867dc 100644 >> --- a/super-recover.c >> +++ b/super-recover.c >> @@ -292,9 +292,6 @@ int btrfs_recover_superblocks(const char *dname, >> no_recover: >> recover_err_str(ret); >> free_recover_superblock(&recover); >> - /* check if we have freed fs_devices in close_ctree() */ >> - if (!root) >> - btrfs_close_devices(recover.fs_devices); >> return ret; >> } >> >>
====== RUN MAYFAIL /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch ERROR: tree_root block unaligned: 33554431 ERROR: superblock checksum matches but it has invalid members ERROR: tree_root block unaligned: 33554431 ERROR: superblock checksum matches but it has invalid members ERROR: tree_root block unaligned: 33554431 ERROR: superblock checksum matches but it has invalid members ERROR: failed to add chunk map start=12582912 len=8454144: -17 (File exists) Couldn't read chunk tree failed (ignored, ret=139): /home/adam/btrfs/btrfs-progs/btrfs rescue super-recover -y -v /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-200409.raw.restored.scratch mayfail: returned code 139 (SEGFAULT), not ignored test failed for case 007-simple-super-recover ------ [CAUSE] In __open_ctree_fd(), if we have valid @open_ctree_flags and btrfs_scan_fs_devices() successes without problem, no matter what happens we will call btrfs_close_devices(), thus free all related devices. In super-recover, before we call open_ctree(), we have called btrfs_scan_fs_devices() already, so btrfs_scan_fs_devices() should not fail in open_ctree(), fs_devices will always be freed in open_ctree() or close_ctree(). [FIX] So in super-recover.c, we should not call btrfs_close_devices(), or we will find fs_devices->list get poisoned, and trigger segfault when exiting. Signed-off-by: Qu Wenruo <wqu@suse.com> --- super-recover.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/super-recover.c b/super-recover.c index 880fd7712546..86b3df9867dc 100644 --- a/super-recover.c +++ b/super-recover.c @@ -292,9 +292,6 @@ int btrfs_recover_superblocks(const char *dname, no_recover: recover_err_str(ret); free_recover_superblock(&recover); - /* check if we have freed fs_devices in close_ctree() */ - if (!root) - btrfs_close_devices(recover.fs_devices); return ret; }