On execve[at], we are zero'ing out most of the thread register state
including gpr[0], which contains the syscall number. Due to this, we
fail to trigger the syscall exit tracepoint properly. Fix this by
retaining gpr[0] in the thread register state.
Before this patch:
# tail /sys/kernel/debug/tracing/trace
cat-123 [000] ..... 61.449351: sys_execve(filename:
7fffa6b23448, argv:
7fffa6b233e0, envp:
7fffa6b233f8)
cat-124 [000] ..... 62.428481: sys_execve(filename:
7fffa6b23448, argv:
7fffa6b233e0, envp:
7fffa6b233f8)
echo-125 [000] ..... 65.813702: sys_execve(filename:
7fffa6b23378, argv:
7fffa6b233a0, envp:
7fffa6b233b0)
echo-125 [000] ..... 65.822214: sys_execveat(fd: 0,
filename:
1009ac48, argv:
7ffff65d0c98, envp:
7ffff65d0ca8, flags: 0)
After this patch:
# tail /sys/kernel/debug/tracing/trace
cat-127 [000] ..... 100.416262: sys_execve(filename:
7fffa41b3448, argv:
7fffa41b33e0, envp:
7fffa41b33f8)
cat-127 [000] ..... 100.418203: sys_execve -> 0x0
echo-128 [000] ..... 103.873968: sys_execve(filename:
7fffa41b3378, argv:
7fffa41b33a0, envp:
7fffa41b33b0)
echo-128 [000] ..... 103.875102: sys_execve -> 0x0
echo-128 [000] ..... 103.882097: sys_execveat(fd: 0,
filename:
1009ac48, argv:
7fffd10d2148, envp:
7fffd10d2158, flags: 0)
echo-128 [000] ..... 103.883225: sys_execveat -> 0x0
Cc: stable@vger.kernel.org
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Sumit Dubey2 <Sumit.Dubey2@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220609103328.41306-1-naveen.n.rao@linux.vnet.ibm.com
tm_reclaim_current(0);
#endif
- memset(regs->gpr, 0, sizeof(regs->gpr));
+ memset(®s->gpr[1], 0, sizeof(regs->gpr) - sizeof(regs->gpr[0]));
regs->ctr = 0;
regs->link = 0;
regs->xer = 0;