On all of our platforms, db_expr_t is a signed integer while
db_addr_t is an unsigned integer value. db_search_symbol used variables
of type db_expr_t to hold the current offset of the requested address from
the "best" symbol found so far. This value was initialized to '~0'.
When a new symbol is found from a symbol table, the associated diff for the
new symbol is compared against the existing value as 'if (newdiff < diff)'
to determine if the new symbol had a smaller diff and was thus a closer
match.
On 64-bit MIPS, the '~0' was treated as a negative value (-1). A lookup
that found a perfect match of an address against a symbol returned a diff
of 0. However, in signed comparisons, 0 is not less than -1. As a result,
DDB on 64-bit MIPS never resolved any addresses to symbols. Workaround
this by using casts to force an unsigned comparison.
Probably the diff returned from db_search_symbol() and X_db_search_symbol()
should be changed to a db_addr_t instead of a db_expr_t as it is an
unsigned value (and is an offset of an address, so should fit in the same
size as an address).
Sponsored by: DARPA / AFRL
When the kernel debugger is entered, makectx() is called to store
appropriate state from the trapframe for the debugger into a global
kdb_pcb used as the thread context of the thread entering the
debugger. Stack unwinders for DDB called via db_trace_thread() are
supposed to then use this saved context so that the stack trace for
the current thread starts at the location of the event that triggered
debugger entry.
MIPS was instead starting the stack trace of the current thread from
the context of db_trace_thread itself and unwinding back out through
the debugger to the original frame. Fix a couple of things to bring
MIPS inline with other platforms:
- Fix makectx() to store the PC, SP, and RA in the right portion of
the PCB used by db_trace_thread().
- Fix db_trace_thread() to always use kdb_thr_ctx() (and thus kdb_pcb
for the debugger thread).
- Move the logic for tracing curthread from within the current
function into db_trace_self() to match other architectures.
Sponsored by: DARPA / AFRL
Linux list_for_each_entry() does not neccessarily end with the iterator
NULL (it may be an offset from NULL if the list member is not the first
element of the member struct).
Reported by: Coverity
CID: 1366940
Reviewed by: hselasky@
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8780
This fixes backtraces from DDB in n32 kernels as uintptr_t is only a
uint32_t. In particular, the upper 32-bits of each register value were
treated as the register's value breaking both the output of register
values, but also the values of 'ra' and 'sp' required to walk up to the
previous frame.
Sponsored by: DARPA / AFRL
This avoids a race with readers such as dladdr(3)/dlinfo(3)/dlsym(3) and
the atexit(3) handler. This race was introduced in r294373.
Reviewed by: markj, kib, kan
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
This commit corrects print of nomatch (newline was too early) and fix
unit number for new child in ar5315_spi (was 0, now is -1 to calculate it
according to actual system state)
Submitted by: Hiroki Mori <yamori813@yahoo.co.jp>
Reviewed by: ray, loos, mizhka
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D8749
My plan is to change this function's prototype at some point in the
future to add a new label argument, which can be used to export all of
sysctl as metrics that can be scraped by Prometheus. Switch over this
caller to use the macro wrapper counterpart.
non-zero sector size. Such a device would be a virtual disk of zero
bytes; clearly not useful, and not something we should try to attach.
As a fortuitous side effect, checking that these values are non-zero
here results in them not *becoming* zero later on the function. This
odd behaviour began with r309124 (clang 3.9.0) but is challenging to
debug; making any changes to this function whatsoever seems to affect
the llvm optimizer behaviour enough to make the unexpected zeroing of
the sector_size variable cease.
PR: 215209
Security: The potential for variables to unexpectedly become zero
has worrying consequences for security in general, but
not so much in this particular context.
Up until r295436 GPT timer in i.MX6 Dual dts used the same compatiblity
string as i.MX6 Quad. After the sync up with Linux in r295436, GPT timer
stopped getting attached on the i.MX6 Dual
MFC after: 3 days
