[GitHub] ncasaril opened a new issue #1080: fcb doesn't handle flash error well - infinite loop

[GitBox <gi...@apache.org>]

ncasaril opened a new issue #1080: fcb doesn't handle flash error well - infinite loop
URL: https://github.com/apache/mynewt-core/issues/1080
 
 
   I store config using config_fcb in an external flash. Sometimes this flash plays up and trips fcb into an infinite loop from what it seems. 
   
   In the backtrack below: 
   
   - we're starting out in fcb_walk
   - enter the while loop running fcb_getnext_nolock
   - in fcb_getnext_nolock it calls fcb_elem_info
   - fcb_elem_info returns **FCB_ERR_FLASH** (as fcb_elem_crc8 fails with this rc)
   - fcb_getnext_nolock only handles **FCB_ERR_CRC** or **FCB_ERR_NOVAR** otherwise just return 0 to the calling fcb_walk
   - fcb_walk in turn tries to call fcb_getnext_nolock and we're back to the beginning. 
   
   As this happens when config_fcb is trying to read it's config at sysinit, sanity is not yet started. 
   
   ```
   #0  fcb_elem_info (fcb=fcb@entry=0x20001804 <config_init_conf_fcb+8>, loc=loc@entry=0x20002608 <os_main_stack+1920>) at repos/apache-mynewt-core/fs/fcb/src/fcb_elem_info.c:101
   #1  0x00032976 in fcb_getnext_in_area (fcb=0x20001804 <config_init_conf_fcb+8>, loc=0x20002608 <os_main_stack+1920>) at repos/apache-mynewt-core/fs/fcb/src/fcb_getnext.c:29
   #2  0x000329f6 in fcb_getnext_nolock (fcb=fcb@entry=0x20001804 <config_init_conf_fcb+8>, loc=loc@entry=0x20002608 <os_main_stack+1920>) at repos/apache-mynewt-core/fs/fcb/src/fcb_getnext.c:80
   #3  0x00032b40 in fcb_walk (fcb=0x20001804 <config_init_conf_fcb+8>, fap=fap@entry=0x0, cb=cb@entry=0x306e5 <conf_fcb_load_cb>, cb_arg=cb_arg@entry=0x20002630 <os_main_stack+1960>) at repos/apache-mynewt-core/fs/fcb/src/fcb_walk.c:40
   #4  0x00030736 in conf_fcb_load (cs=<optimized out>, cb=<optimized out>, cb_arg=<optimized out>) at repos/apache-mynewt-core/sys/config/src/config_fcb.c:128
   #5  0x00030630 in conf_load () at repos/apache-mynewt-core/sys/config/src/config_store.c:77
   #6  0x00015d6a in lnode_tasks_pkg_init () at mgmt/lnode_tasks/src/lnode_tasks_sysinit.c:45
   #7  0x0000af14 in sysinit_app () at bin/targets/lnode_main/generated/src/lnode_main-sysinit-app.c:182
   #8  0x00006468 in main (argc=<optimized out>, argv=<optimized out>) at apps/lnode/src/main.c:76
   ```

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