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hw_breakpoints: Release the bp slot if arch_validate_hwbkpt_settings(…
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…) fails.

On a given architecture, when hardware breakpoint registration fails
due to un-supported access type (read/write/execute), we lose the bp
slot since register_perf_hw_breakpoint() does not release the bp slot
on failure.
Hence, any subsequent hardware breakpoint registration starts failing
with 'no space left on device' error.

This patch introduces error handling in register_perf_hw_breakpoint()
function and releases bp slot on error.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
LKML-Reference: <20100121125516.GA32521@in.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Mahesh Salgaonkar authored and Frederic Weisbecker committed Jan 28, 2010
1 parent 7f5102c commit b23ff0e
Showing 1 changed file with 4 additions and 0 deletions.
4 changes: 4 additions & 0 deletions kernel/hw_breakpoint.c
Original file line number Diff line number Diff line change
Expand Up @@ -296,6 +296,10 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
if (!bp->attr.disabled || !bp->overflow_handler)
ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);

/* if arch_validate_hwbkpt_settings() fails then release bp slot */
if (ret)
release_bp_slot(bp);

return ret;
}

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